Add AMPB browser source build spike tools

tools/browser-source-report.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+set -eu
+
+root="${AMPB_BROWSER_BUILD_ROOT:-/tmp/ampb-browser-build}"
+
+report_repo() {
+  label="$1"
+  path="$2"
+  if [ -d "$path/.git" ]; then
+    printf '%s_DIR=%s\n' "$label" "$path"
+    printf '%s_REMOTE=%s\n' "$label" "$(git -C "$path" remote get-url origin)"
+    printf '%s_REV=%s\n' "$label" "$(git -C "$path" rev-parse --short HEAD)"
+  else
+    printf '%s_DIR=%s\n' "$label" "$path"
+    printf '%s_STATUS=missing\n' "$label"
+  fi
+}
+
+report_repo AMPB_GECKO "$root/src/gecko-dev"
+report_repo AMPB_TOR_BROWSER_BUILD "$root/src/tor-browser-build"
+report_repo AMPB_LEGACY_FIREFOX_ANDROID "$root/src/firefox-android"