Linter replaces MDN url anchor when page is now redirecting to anchor

What type of issue is this?

Linter issue

What is the issue?

If a feature has an mdn_url that points to an anchor of an MDN page, and that page is removed and redirected to another page with an anchor, then this redirect target replaces the mdn_url and the current anchor gets lost, even if the redirect target has an anchor corresponding to the old mdn_url.

See: https://github.com/mdn/browser-compat-data/pull/25138/commits/4c58e86a0317f28a7ada2d5f9d6daa5f55f711f0

diff --git a/http/headers/Content-Security-Policy.json b/http/headers/Content-Security-Policy.json
index 6c1ee46a99cd45..64dc4a85df7bdc 100644
--- a/http/headers/Content-Security-Policy.json
+++ b/http/headers/Content-Security-Policy.json
@@ -746,7 +746,7 @@
         "report-sample": {
           "__compat": {
             "description": "`report-sample` source value",
-            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#report-sample",
+            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy#fetch_directive_syntax",
             "support": {
               "chrome": {
                 "version_added": "59"
@@ -1152,7 +1152,7 @@
         "strict-dynamic": {
           "__compat": {
             "description": "`strict-dynamic` source value",
-            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#strict-dynamic",
+            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy#fetch_directive_syntax",
             "support": {
               "chrome": {
                 "version_added": "52"
@@ -1338,7 +1338,7 @@
         "unsafe-hashes": {
           "__compat": {
             "description": "`unsafe-hashes` source value",
-            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#unsafe-hashes",
+            "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy#fetch_directive_syntax",
             "support": {
               "chrome": {
                 "version_added": "69"

What behavior were you expecting?

We should have not overwritten these specific MDN urls.

What version(s) of BCD is the issue present in?

• The current BCD release
• The current version of the main branch

Do you have anything more you want to share?

No response

Start by reproducing the linter change shown in Content-Security-Policy.json and inspect the linter logic that follows MDN redirects. Check how URLs with anchors are handled when both the original and redirect target contain anchors. Done means the existing anchor is preserved rather than replaced by the redirect target's page URL.