http://manual.koha-community.org/3.22/en/circfaq.html#printoverduefaq contains "The print and email overdues use the same notice file. The print notices for holds are different -- there's a separate HOLD_PRINT notice file and the system uses it if there's no email address. Then a nightly cron job runs to gather those up from the message queue and put them in an HTML file in the notice directory, as above. The cron entry is gather_print_notices.pl /tmp/noticedir" This is out of date in the following respects: 1) HOLD_PRINT no longer exists -- this is handled by the print message under the HOLD letter. 2) gather_print_notices.pl now supports printing overdue notices.
Verified, HOLD_PRINT no longer exists as you can now define a print template for any notice. Needs to be removed.
I sent in a merge request to the manual. https://gitlab.com/koha-community/koha-manual/merge_requests/187/commits