The current logic for where to enable visual enhancements is as follows:
- Any page in a _talk namespace (T325417)
- Or any page with __NEWSECTIONLINK__ (T331635)
- (excluding the main namespace as that is likely a false positive, unless the main namespace has been configured for signatures)
In T331635 we decided that __NEWSECTIONLINK__ was a pretty good indicator that a non-talk namespace page contained discussion, such as:
https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)
This doesn't catch archives of that page, as they deliberate omit __NEWSECTIONLINK__ to discourage editing archived pages:
https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)/Archive_215
These page do contain the __ARCHIVEDTALK__ magic word (via a template), to suppress reply links. This is an even better indicator that the page contains discussions. (Note that __NOTALK__ can used to suppress reply links in cases where signatures are used in non-discussion contexts).
Testing
Non-talk pages which are marked with the archived header, or manually with __ARCHIVEDTALK__ get talk page styling, e.g. https://en.wikipedia.beta.wmflabs.org/wiki/Wikipedia:Village_pump_(proposals)/Archive_84