The link is missing the /r prefix in the path. The [edit] was introduced by https://gerrit-review.googlesource.com/c/gitiles/+/392465 (released in gitiles 1.5.0). It is implemented differently from the other urls.

The base URL is set by the Gerrit Gitiles plugins to https://gerrit.wikimedia.org/r which includes the /r path prefix. However the code appends /admin... which is an absolute path, and that causes URI.resolve() to drop the prefix:

jshell> new URI("https://example.org/r").resolve("/admin/repos/edit");
                                    ^^
$2 ==> https://example.org/admin/repos/edit
                         ^^^____oops

Fix:

https://gerrit-review.googlesource.com/c/gitiles/+/514361 Tests: update path prefix in git urls
https://gerrit-review.googlesource.com/c/gitiles/+/514362 Fix edit link when base URL has a path