Thank you Driv. I see your linked posts from 2012 regarding the loss (zeroed-out) of the config.inc.php file, and present you with the following:

UBB.threads 7.6.1 Changelog (January 1, 2018) -
[NEW] The current forum config file is now backed up before new changes are saved. A forum owner can now roll back to their backup config file, if the new one gets corrupted during its creation.
https://www.ubbcentral.com/forums/u.../7-6-1-1-changelog-discussion#Post260743

config-bak.inc.php is mentioned in this thread's OP and a few other times in the replies. As a result of this new feature added in 2018, It appears that Morgan was able to make use of this auto-backed up configuration file for his main settings, in conjunction with a previous backup of his forum header/footers.