This is sort of a follow-on to bug #57594, but seems separate enough to warrant its own bug report.

Prior to commit b2284ab0, groff's English hyphenation exceptions file (tmac/hyphenex.en) was a copy of the TeX file ushyphex_tex, last synced with the TeX version in 2017 (commit 905c3978).

The TeX list has been updated since then (in January 2021), adding 365 entries and correcting two (Ma-la-ya-lam becoming Mal-a-ya-lam, and sur-ge-ries becoming sur-ger-ies)—and, curiously, removing 53.

The commit log for b2284ab0 makes clear that the TeX exceptions file is based only on the Knuth patterns, and that many of the entries are unnecessary when using the additional Kuikens patterns.

This raises the question of how to sync with updates to the TeX exceptions list now and going forward.  I presume that Branden's method for trimming the list was mostly automated, not manual.  If so, this code should live somewhere accessible to all groff developers.

Another issue is that in some of the before/after examples cited in the b2284ab0 commit log, the "before" break points seem clearly superior.  So these might be exceptions that groff needs that TeX does not, meaning groff would have to maintain its own separate list of exceptions to augment the TeX list.

Finally, once a procedure is worked out for syncing, processing, and augmenting the exceptions file, should these steps be added to FOR-RELEASE?