--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -8480,16 +8480,26 @@
   "DEVTOOLS_DEBUGGER_DISPLAY_SOURCE_REMOTE_MS": {
     "record_in_processes": ["main", "content"],
     "expires_in_version": "never",
     "kind": "exponential",
     "high": 10000,
     "n_buckets": 1000,
     "description": "The time (in milliseconds) that it took to display a selected source to the user."
   },
+  "DEVTOOLS_DEBUGGER_LOAD_SOURCE_MS": {
+    "record_in_processes": ["main", "content"],
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org", "hkirschner@mozilla.com"],
+    "bug_numbers": [1429047],
+    "expires_in_version": "never",
+    "kind": "exponential",
+    "high": 10000,
+    "n_buckets": 100,
+    "description": "The time (in milliseconds) that it took to load a source for the user."
+  },
   "DEVTOOLS_ABOUT_DEVTOOLS_OPENED_KEY": {
     "record_in_processes": ["main"],
     "alert_emails": ["dev-developer-tools@lists.mozilla.org", "hkirschner@mozilla.com"],
     "bug_numbers": [1412029],
     "expires_in_version": "63",
     "kind": "categorical",
     "labels": ["toggleToolbox", "toggleToolboxF12", "inspector", "webconsole", "jsdebugger", "netmonitor", "toggleToolbar", "webide", "browserToolbox", "browserConsole", "responsiveDesignMode", "scratchpad", "styleeditor", "performance", "storage", "dom"],
     "description": "Records the key shortcut passed to open the about:devtools page."

--- a/toolkit/components/telemetry/Scalars.yaml
+++ b/toolkit/components/telemetry/Scalars.yaml
@@ -964,16 +964,29 @@ devtools.onboarding:
       How many users are flagged as existing devtools users.
     expires: "63"
     kind: boolean
     notification_emails:
       - dev-developer-tools@lists.mozilla.org, jdescottes@mozilla.com
     record_in_processes:
       - 'main'
 
+devtools.debugger:
+  source_selected:
+    bug_numbers:
+      - 1429047
+    description: Number of times a source is selected
+    expires: never
+    kind: uint
+    notification_emails:
+      - dev-developer-tools@lists.mozilla.org
+    release_channel_collection: opt-out
+    record_in_processes:
+      - 'main'
+
 navigator.storage:
   estimate_count:
     bug_numbers:
       - 1359708
     description: >
       Number of times navigator.storage.estimate has been used.
     expires: "60"
     kind: uint