There is some mess in game log

[moonfather1]

on startup GC outputs a bunch of warnings to the log saying "Unknown recipe category".

mc 1.20.1

[Hojosa]

looking at the output, its because our custom recipes have no recipe category assigned.
that should be fixable by adding "category": "misc", etc to the json files

[Alatyami]

Looking into this ... for custom recipe serializer, we have not been able to populate the category as it is not part of the Recipe interface.

[Alatyami]

There is a way to add a custom recipe type to the recipe book.

[Alatyami]

Moving to next release.

[moonfather1]

why would you add anything to the recipe book?

but really, there is a lot of error text in the log.

[Alatyami]

Mojang tries to add it to recipe book from the recipe registry. This is a common problem that all modders have if you make a recipe serializer. When I did the porting to 1.20 there wasn't a way to squash the warning.