Added guard against undefined branchBuilds and fixed releases format …

…in json output

lib/commands/sdk.js

@@ -176,17 +176,23 @@ async function list(logger, config, cli) {
 
 		const obj = {
 			activeSDK,
-			branch: branchBuilds.length ? {
+			branch: branchBuilds?.length ? {
 				[cli.argv.branch]: branchBuilds
 			} : {},
-			branches,
+			branches: {
+				defaultBranch: 'master',
+				branches: branches || []
+			},
 			defaultInstallLocation,
 			installLocations: locations,
 			installed: vers.reduce((obj, v) => {
 				obj[v] = sdks[v].path;
 				return obj;
 			}, {}),
-			releases,
+			releases: releases && releases.reduce((obj, { name, assets }) => {
+				obj[name] = assets.find(a => a.os === os).url;
+				return obj;
+			}, {}) || {},
 			sdks
 		};
 
@@ -274,7 +280,7 @@ ${r.type !== 'ga' ? '  [unstable]'.grey : i++ === 0 ? '  [latest stable]'.green
 			logger.log(`Run '${`${cli.argv.$} sdk --branches`.cyan}' for a list of available branches.\n`);
 		} else {
 			logger.log(`'${cli.argv.branch}' Branch Builds:`);
-			if (branchBuilds.length) {
+			if (branchBuilds?.length) {
 				for (const b of branchBuilds) {
 					const dt = Intl.DateTimeFormat('en-US', { dateStyle: 'short' }).format(new Date(b.date));
 					logger.log(`   ${b.name.cyan}\