Just noticed this oddity…
G’MIC command line help always points to an “oldtutorial” URL even if one never existed, as in -store, which was composed fresh as a 2.9 tutorial; an “oldtutorial” form was never written:
The Technical Reference Page page has a Tutorial Page for -store that points to the right place. Alas, at the bottom of that tutorial page, there is an expansion of $gmic -h store which, as you know, is just a reproduction of the shell command and therefore points to the phantom tutorial. That could be a trifling confusing.
Only done spot-checking, but it seems that all command line help references a page in the oldtutorial section, whether the target URL exists or not. 
This is Version 2.9.8 (pre-release #210605)
Edit:
Rummaging around gmic/src/gmic_stdlib.gmic:4151-4252
- 4230-4231 - I get the impression that - regardless of flags being set - the eventual setting of
$urlwill have an ‘oldtutorial’ form. Haven’t grasped the logic yet on how flags are set.
Bookmarked for further contemplation, when east-pointing shadows grow long here on the Eastern Seaboard of North America. Civilization calls now…