diff --git a/CHANGELOG.md b/CHANGELOG.md
index ede7afe619..8751f5c996 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 ## Version `v0.27.19`
 
 * ![Enhancement][badge-enhancement] On the HTML search page, pressing enter no longer causes the page to refresh (and therefore does not trigger the slow search index rebuild). ([#1728][github-1728], [#1833][github-1833], [#1834][github-1834])
+* ![Enhancement][badge-enhancement] For the `edit_link` keyword to `HTML()`, Documenter automatically tries to figure out if the remote default branch is `main`, `master`, or something else. It will print a warning if it is unable to reliably determine either `edit_link` or `devbranch` (for `deploydocs`). ([#1827][github-1827], [#1829][github-1829])
 
 ## Version `v0.27.18`
 
@@ -1046,7 +1047,9 @@
 [github-1818]: https://github.com/JuliaDocs/Documenter.jl/pull/1818
 [github-1821]: https://github.com/JuliaDocs/Documenter.jl/pull/1821
 [github-1825]: https://github.com/JuliaDocs/Documenter.jl/pull/1825
+[github-1827]: https://github.com/JuliaDocs/Documenter.jl/issues/1827
 [github-1828]: https://github.com/JuliaDocs/Documenter.jl/pull/1828
+[github-1829]: https://github.com/JuliaDocs/Documenter.jl/pull/1829
 [github-1833]: https://github.com/JuliaDocs/Documenter.jl/pull/1833
 [github-1834]: https://github.com/JuliaDocs/Documenter.jl/pull/1834
 <!-- end of issue link definitions -->
diff --git a/src/Documenter.jl b/src/Documenter.jl
index 54fee2e394..6dde3264f3 100644
--- a/src/Documenter.jl
+++ b/src/Documenter.jl
@@ -532,18 +532,7 @@ function deploydocs(;
 
     # Try to figure out default branch (see #1443 and #1727)
     if devbranch === nothing
-        env = copy(ENV)
-        env["GIT_TERMINAL_PROMPT"] = "0"
-        env["GIT_SSH_COMMAND"] = get(env, "GIT_SSH_COMMAND", "ssh -o \"BatchMode yes\"")
-        str = try
-            read(pipeline(ignorestatus(
-                setenv(`git remote show origin`, env; dir=root)
-            ); stderr=devnull), String)
-        catch
-            ""
-        end
-        m = match(r"^\s*HEAD branch:\s*(.*)$"m, str)
-        devbranch = m === nothing ? "master" : String(m[1])
+        devbranch = Utilities.git_remote_head_branch("deploydocs(devbranch = ...)", root)
     end
 
     deploy_decision = deploy_folder(deploy_config;
diff --git a/src/Utilities/Utilities.jl b/src/Utilities/Utilities.jl
index c4cdbf7346..c5187b9277 100644
--- a/src/Utilities/Utilities.jl
+++ b/src/Utilities/Utilities.jl
@@ -785,6 +785,55 @@ function check_strict_kw(strict)
     return nothing
 end
 
+"""
+Calls `git remote show \$(remotename)` to try to determine the main (development) branch
+of the remote repository. Returns `master` and prints a warning if it was unable to figure
+it out automatically.
+
+`root` is the the directory where `git` gets run. `varname` is just informational and used
+to construct the warning messages.
+"""
+function git_remote_head_branch(varname, root; remotename = "origin", fallback = "master")
+    env = copy(ENV)
+    env["GIT_TERMINAL_PROMPT"] = "0"
+    env["GIT_SSH_COMMAND"] = get(env, "GIT_SSH_COMMAND", "ssh -o \"BatchMode yes\"")
+    cmd = `git remote show $(remotename)`
+    stderr_output = IOBuffer()
+    git_remote_output = try
+        # Older Julia versions don't support pipeline-ing into IOBuffer.
+        stderr_redirect = if VERSION >= v"1.6.0"
+            stderr_output
+        else
+            write(stderr_output, "(no output redirect on Julia $VERSION)")
+            devnull
+        end
+        read(pipeline(setenv(cmd, env; dir=root); stderr = stderr_redirect), String)
+    catch e
+        @warn """
+        Unable to determine $(varname) from remote HEAD branch, defaulting to "$(fallback)".
+        Calling `git remote` failed with an exception. Set JULIA_DEBUG=Documenter to see the error.
+        Unless this is due to a configuration error, the relevant variable should be set explicitly.
+        """
+        @debug "Command: $cmd" exception = (e, catch_backtrace()) stderr = String(take!(stderr_output))
+        return fallback
+    end
+    m = match(r"^\s*HEAD branch:\s*(.*)$"m, git_remote_output)
+    if m === nothing
+        @warn """
+        Unable to determine $(varname) from remote HEAD branch, defaulting to "$(fallback)".
+        Failed to parse the `git remote` output. Set JULIA_DEBUG=Documenter to see the output.
+        Unless this is due to a configuration error, the relevant variable should be set explicitly.
+        """
+        @debug """
+        stdout from $cmd:
+        $(git_remote_output)
+        """
+        fallback
+    else
+        String(m[1])
+    end
+end
+
 include("DOM.jl")
 include("MDFlatten.jl")
 include("TextDiff.jl")
diff --git a/src/Writers/HTMLWriter.jl b/src/Writers/HTMLWriter.jl
index 3b5bf3d3da..688b6853ac 100644
--- a/src/Writers/HTMLWriter.jl
+++ b/src/Writers/HTMLWriter.jl
@@ -420,7 +420,7 @@ struct HTML <: Documenter.Writer
     function HTML(;
             prettyurls    :: Bool = true,
             disable_git   :: Bool = false,
-            edit_link     :: Union{String, Symbol, Nothing, Default} = Default("master"),
+            edit_link     :: Union{String, Symbol, Nothing, Default} = Default(Utilities.git_remote_head_branch("HTML(edit_link = ...)", Utilities.currentdir())),
             canonical     :: Union{String, Nothing} = nothing,
             assets        :: Vector = String[],
             analytics     :: String = "",
diff --git a/test/TestUtilities.jl b/test/TestUtilities.jl
index cc8b10f048..dacc18f9d5 100644
--- a/test/TestUtilities.jl
+++ b/test/TestUtilities.jl
@@ -2,7 +2,7 @@ module TestUtilities
 using Test
 import IOCapture
 
-export @quietly
+export @quietly, trun
 
 const QUIETLY_LOG = joinpath(@__DIR__, "quietly.log")
 
@@ -85,4 +85,27 @@ function is_success(x)
     return false
 end
 
+function trun(cmd::Base.AbstractCmd)
+    buffer = IOBuffer()
+    cmd_redirected = if VERSION < v"1.6.0"
+        # Okay, older Julia versions have a missing method, which don't allow a redirect:
+        #   MethodError: no method matching rawhandle(::Base.GenericIOBuffer{Array{UInt8,1}})
+        # Not sure when it was exactly fixed, but 1.6 seems to work fine.
+        write(buffer, "no output recorded")
+        cmd
+    else
+        pipeline(cmd; stdin = devnull, stdout = buffer, stderr = buffer)
+    end
+    try
+        run(cmd_redirected)
+        return true
+    catch e
+        @error """
+        Running external program $(cmd) failed, output:
+        $(String(take!(buffer)))
+        """ exception = (e, catch_backtrace())
+        return false
+    end
+end
+
 end
diff --git a/test/doctests/doctests.jl b/test/doctests/doctests.jl
index be4151eca4..7571f4c0cf 100644
--- a/test/doctests/doctests.jl
+++ b/test/doctests/doctests.jl
@@ -36,6 +36,7 @@ function run_makedocs(f, mdfiles, modules=Module[]; kwargs...)
     c = IOCapture.capture(rethrow = InterruptException) do
         makedocs(
             sitename = " ",
+            format = Documenter.HTML(edit_link = "master"),
             root = dir,
             modules = modules;
             kwargs...
diff --git a/test/utilities.jl b/test/utilities.jl
index 4430d79f6d..5024158f3b 100644
--- a/test/utilities.jl
+++ b/test/utilities.jl
@@ -170,15 +170,15 @@ end
         mkpath(path_repo)
         cd(path_repo) do
             # Create a simple mock repo in a temporary directory with a single file.
-            @test success(`git init`)
-            @test success(`git config user.email "tester@example.com"`)
-            @test success(`git config user.name "Test Committer"`)
-            @test success(`git remote add origin git@github.com:JuliaDocs/Documenter.jl.git`)
+            @test trun(`git init`)
+            @test trun(`git config user.email "tester@example.com"`)
+            @test trun(`git config user.name "Test Committer"`)
+            @test trun(`git remote add origin git@github.com:JuliaDocs/Documenter.jl.git`)
             mkpath("src")
             filepath = abspath(joinpath("src", "SourceFile.jl"))
             write(filepath, "X")
-            @test success(`git add -A`)
-            @test success(`git commit -m"Initial commit."`)
+            @test trun(`git add -A`)
+            @test trun(`git commit -m"Initial commit."`)
 
             # Run tests
             commit = Documenter.Utilities.repo_commit(filepath)
@@ -198,7 +198,7 @@ end
         # Test worktree
         path_worktree = joinpath(path, "worktree")
         cd("$(path_repo)") do
-            @test success(`git worktree add $(path_worktree)`)
+            @test trun(`git worktree add $(path_worktree)`)
         end
         cd("$(path_worktree)") do
             filepath = abspath(joinpath("src", "SourceFile.jl"))
@@ -221,15 +221,15 @@ end
         path_submodule = joinpath(path, "submodule")
         mkpath(path_submodule)
         cd(path_submodule) do
-            @test success(`git init`)
-            @test success(`git config user.email "tester@example.com"`)
-            @test success(`git config user.name "Test Committer"`)
+            @test trun(`git init`)
+            @test trun(`git config user.email "tester@example.com"`)
+            @test trun(`git config user.name "Test Committer"`)
             # NOTE: the target path in the `git submodule add` command is necessary for
             # Windows builds, since otherwise Git claims that the path is in a .gitignore
             # file.
-            @test success(`git submodule add $(path_repo) repository`)
-            @test success(`git add -A`)
-            @test success(`git commit -m"Initial commit."`)
+            @test trun(`git submodule add $(path_repo) repository`)
+            @test trun(`git add -A`)
+            @test trun(`git commit -m"Initial commit."`)
         end
         path_submodule_repo = joinpath(path, "submodule", "repository")
         @test isdir(path_submodule_repo)
@@ -539,6 +539,53 @@ end
             @test err.msg == "tag :foo is not a valid Documenter error"
         end
     end
+
+    @testset "git_remote_head_branch" begin
+
+        function git_create_bare_repo(path; head = nothing)
+            mkdir(path)
+            @test trun(`git -C $(path) init --bare`)
+            @test isfile(joinpath(path, "HEAD"))
+            if head !== nothing
+                write(joinpath(path, "HEAD"), """
+                ref: refs/heads/$(head)
+                """)
+            end
+            mktempdir() do subdir_path
+                # We need to commit something to the non-standard branch to actually
+                # "activate" the non-standard HEAD:
+                head = (head === nothing) ? "master" : head
+                @test trun(`git clone $(path) $(subdir_path)`)
+                @test trun(`git -C $(subdir_path) config user.email "tester@example.com"`)
+                @test trun(`git -C $(subdir_path) config user.name "Test Committer"`)
+                @test trun(`git -C $(subdir_path) checkout -b $(head)`)
+                @test trun(`git -C $(subdir_path) commit --allow-empty -m"initial empty commit"`)
+                @test trun(`git -C $(subdir_path) push --set-upstream origin $(head)`)
+            end
+        end
+
+        mktempdir() do path
+            cd(path) do
+                # If there is no parent remote repository, we should get a warning and the fallback value:
+                @test (@test_logs (:warn,) Documenter.Utilities.git_remote_head_branch(".", pwd(); fallback = "fallback")) == "fallback"
+                @test (@test_logs (:warn,) Documenter.Utilities.git_remote_head_branch(".", pwd())) == "master"
+                # We'll set up two "remote" bare repositories with non-standard HEADs:
+                git_create_bare_repo("barerepo", head = "maindevbranch")
+                git_create_bare_repo("barerepo_other", head = "main")
+                # Clone barerepo and test git_remote_head_branch:
+                @test trun(`git clone barerepo/ local/`)
+                @test Documenter.Utilities.git_remote_head_branch(".", "local") == "maindevbranch"
+                # Now, let's add the other repo as another remote, and fetch the HEAD for that:
+                @test trun(`git -C local/ remote add other ../barerepo_other/`)
+                @test trun(`git -C local/ fetch other`)
+                @test Documenter.Utilities.git_remote_head_branch(".", "local") == "maindevbranch"
+                @test Documenter.Utilities.git_remote_head_branch(".", "local"; remotename = "other") == "main"
+                # Asking for a nonsense remote should also warn and drop back to fallback:
+                @test (@test_logs (:warn,) Documenter.Utilities.git_remote_head_branch(".", pwd(); remotename = "nonsense", fallback = "fallback")) == "fallback"
+                @test (@test_logs (:warn,) Documenter.Utilities.git_remote_head_branch(".", pwd(); remotename = "nonsense")) == "master"
+            end
+        end
+    end
 end
 
 end