PHP 8.3 (maybe lower) TypeError set_exception_handler()

[yorkshire-pudding]

Seen in logs of docs.b.org after upgrade to PHP 8.3

TypeError: set_exception_handler(): Argument #1 ($callback) must be a valid callback or null, class PGPEditor does not have a method "exception_handler" in set_exception_handler() (line 126 of /home/docs/repo/www/modules/contrib/api/grammar_parser/parser.inc)

The adjacent logs suggest this is occurring on certain core files:

• core/modules/system/system.install
• core/includes/ajax.inc

There is also an adjacent warning:

Bad HTTP response from PHP branch PHP functions.