diff --git a/base/loading.jl b/base/loading.jl
index cb4bdf518b816..7f359695a290a 100644
--- a/base/loading.jl
+++ b/base/loading.jl
@@ -1124,10 +1124,10 @@ function _include_from_serialized(pkg::PkgId, path::String, ocachepath::Union{No
     end
 
     if ocachepath !== nothing
-        @debug "Loading object cache file $ocachepath for $pkg"
+        @debug "Loading object cache file $ocachepath for $(repr("text/plain", pkg))"
         sv = ccall(:jl_restore_package_image_from_file, Any, (Cstring, Any, Cint, Cstring, Cint), ocachepath, depmods, false, pkg.name, ignore_native)
     else
-        @debug "Loading cache file $path for $pkg"
+        @debug "Loading cache file $path for $(repr("text/plain", pkg))"
         sv = ccall(:jl_restore_incremental, Any, (Cstring, Any, Cint, Cstring), path, depmods, false, pkg.name)
     end
     if isa(sv, Exception)
@@ -1160,7 +1160,7 @@ function _include_from_serialized(pkg::PkgId, path::String, ocachepath::Union{No
             return M
         end
     end
-    return ErrorException("Required dependency $pkg failed to load from a cache file.")
+    return ErrorException("Required dependency $(repr("text/plain", pkg)) failed to load from a cache file.")
 
     finally
         timing_imports && cumulative_compile_timing(false)
@@ -2101,7 +2101,7 @@ function _require(pkg::PkgId, env=nothing)
         path = locate_package(pkg, env)
         if path === nothing
             throw(ArgumentError("""
-                Package $pkg is required but does not seem to be installed:
+                Package $(repr("text/plain", pkg)) is required but does not seem to be installed:
                  - Run `Pkg.instantiate()` to install all recorded dependencies.
                 """))
         end
@@ -2123,7 +2123,7 @@ function _require(pkg::PkgId, env=nothing)
         for (concrete_pkg, concrete_build_id) in _concrete_dependencies
             if pkg == concrete_pkg
                 @warn """Module $(pkg.name) with build ID $((UUID(concrete_build_id))) is missing from the cache.
-                     This may mean $pkg does not support precompilation but is imported by a module that does."""
+                     This may mean $(repr("text/plain", pkg)) does not support precompilation but is imported by a module that does."""
                 if JLOptions().incremental != 0
                     # during incremental precompilation, this should be fail-fast
                     throw(PrecompilableError())
@@ -2157,16 +2157,16 @@ function _require(pkg::PkgId, env=nothing)
                 elseif isa(cachefile, Exception)
                     if precompilableerror(cachefile)
                         verbosity = isinteractive() ? CoreLogging.Info : CoreLogging.Debug
-                        @logmsg verbosity "Skipping precompilation due to precompilable error. Importing $pkg." exception=m
+                        @logmsg verbosity "Skipping precompilation due to precompilable error. Importing $(repr("text/plain", pkg))." exception=m
                     else
-                        @warn "The call to compilecache failed to create a usable precompiled cache file for $pkg" exception=m
+                        @warn "The call to compilecache failed to create a usable precompiled cache file for $(repr("text/plain", pkg))" exception=m
                     end
                     # fall-through to loading the file locally if not incremental
                 else
                     cachefile, ocachefile = cachefile::Tuple{String, Union{Nothing, String}}
                     m = _tryrequire_from_serialized(pkg, cachefile, ocachefile)
                     if !isa(m, Module)
-                        @warn "The call to compilecache failed to create a usable precompiled cache file for $pkg" exception=m
+                        @warn "The call to compilecache failed to create a usable precompiled cache file for $(repr("text/plain", pkg))" exception=m
                     else
                         return m
                     end
@@ -2393,7 +2393,7 @@ function check_src_module_wrap(pkg::PkgId, srcpath::String)
         inside_string && continue
         if contains(s, module_rgx)
             if load_seen
-                throw(ErrorException("Package $pkg source file $srcpath has a using/import before a module declaration."))
+                throw(ErrorException("Package $(repr("text/plain", pkg)) source file $srcpath has a using/import before a module declaration."))
             end
             return true
         end
@@ -2401,7 +2401,7 @@ function check_src_module_wrap(pkg::PkgId, srcpath::String)
             load_seen = true
         end
     end
-    throw(ErrorException("Package $pkg source file $srcpath does not contain a module declaration."))
+    throw(ErrorException("Package $(repr("text/plain", pkg)) source file $srcpath does not contain a module declaration."))
 end
 
 # this is called in the external process that generates precompiled package files
@@ -2480,12 +2480,12 @@ function create_expr_cache(pkg::PkgId, input::String, output::String, output_o::
     end
 
     if output_o !== nothing
-        @debug "Generating object cache file for $pkg"
+        @debug "Generating object cache file for $(repr("text/plain", pkg))"
         cpu_target = get(ENV, "JULIA_CPU_TARGET", nothing)
         opt_level = Base.JLOptions().opt_level
         opts = `-O$(opt_level) --output-o $(output_o) --output-ji $(output) --output-incremental=yes`
     else
-        @debug "Generating cache file for $pkg"
+        @debug "Generating cache file for $(repr("text/plain", pkg))"
         cpu_target = nothing
         opts = `-O0 --output-ji $(output) --output-incremental=yes`
     end
@@ -2553,7 +2553,7 @@ for important notes.
 function compilecache(pkg::PkgId, internal_stderr::IO = stderr, internal_stdout::IO = stdout; reasons::Union{Dict{String,Int},Nothing}=Dict{String,Int}())
     @nospecialize internal_stderr internal_stdout
     path = locate_package(pkg)
-    path === nothing && throw(ArgumentError("$pkg not found during precompilation"))
+    path === nothing && throw(ArgumentError("$(repr("text/plain", pkg)) not found during precompilation"))
     return compilecache(pkg, path, internal_stderr, internal_stdout; reasons)
 end
 
@@ -2577,7 +2577,7 @@ function compilecache(pkg::PkgId, path::String, internal_stderr::IO = stderr, in
     end
     # run the expression and cache the result
     verbosity = isinteractive() ? CoreLogging.Info : CoreLogging.Debug
-    @logmsg verbosity "Precompiling $pkg $(list_reasons(reasons))"
+    @logmsg verbosity "Precompiling $(repr("text/plain", pkg)) $(list_reasons(reasons))"
 
     # create a temporary file in `cachepath` directory, write the cache in it,
     # write the checksum, _and then_ atomically move the file to `cachefile`.
@@ -2621,7 +2621,7 @@ function compilecache(pkg::PkgId, path::String, internal_stderr::IO = stderr, in
             # append extra crc to the end of the .ji file:
             open(tmppath, "r+") do f
                 if iszero(isvalid_cache_header(f))
-                    error("Invalid header for $pkg in new cache file $(repr(tmppath)).")
+                    error("Invalid header for $(repr("text/plain", pkg)) in new cache file $(repr(tmppath)).")
                 end
                 seekend(f)
                 write(f, crc_so)
@@ -2692,7 +2692,7 @@ function compilecache(pkg::PkgId, path::String, internal_stderr::IO = stderr, in
     if p.exitcode == 125
         return PrecompilableError()
     else
-        error("Failed to precompile $pkg to $(repr(tmppath)).")
+        error("Failed to precompile $(repr("text/plain", pkg)) to $(repr(tmppath)).")
     end
 end
 
@@ -3283,9 +3283,9 @@ function maybe_cachefile_lock(f, pkg::PkgId, srcpath::String; stale_age=compilec
             pid, hostname, age = invokelatest(parse_pidfile_hook, pidfile)
             verbosity = isinteractive() ? CoreLogging.Info : CoreLogging.Debug
             if isempty(hostname) || hostname == gethostname()
-                @logmsg verbosity "Waiting for another process (pid: $pid) to finish precompiling $pkg. Pidfile: $pidfile"
+                @logmsg verbosity "Waiting for another process (pid: $pid) to finish precompiling $(repr("text/plain", pkg)). Pidfile: $pidfile"
             else
-                @logmsg verbosity "Waiting for another machine (hostname: $hostname, pid: $pid) to finish precompiling $pkg. Pidfile: $pidfile"
+                @logmsg verbosity "Waiting for another machine (hostname: $hostname, pid: $pid) to finish precompiling $(repr("text/plain", pkg)). Pidfile: $pidfile"
             end
             # wait until the lock is available, but don't actually acquire it
             # returning nothing indicates a process waited for another
@@ -3438,7 +3438,7 @@ end
                 # verify that `require(modkey, name(req_modkey))` ==> `req_modkey`
                 pkg = identify_package(modkey, req_modkey.name)
                 if pkg != req_modkey
-                    @debug "Rejecting cache file $cachefile because uuid mapping for $modkey => $req_modkey has changed, expected $modkey => $pkg"
+                    @debug "Rejecting cache file $cachefile because uuid mapping for $modkey => $req_modkey has changed, expected $modkey => $(repr("text/plain", pkg))"
                     record_reason(reasons, "dep uuid changed")
                     return true
                 end
diff --git a/base/pkgid.jl b/base/pkgid.jl
index 20d9de559b334..a3d3ead184bb8 100644
--- a/base/pkgid.jl
+++ b/base/pkgid.jl
@@ -23,7 +23,7 @@ function hash(pkg::PkgId, h::UInt)
     return h
 end
 
-show(io::IO, pkg::PkgId) =
+show(io::IO,  ::MIME"text/plain", pkg::PkgId) =
     print(io, pkg.name, " [", pkg.uuid === nothing ? "top-level" : pkg.uuid, "]")
 
 function binpack(pkg::PkgId)