Updating kry_stdlib from 2.0.9 to 2.0.10 caused a crash in 'Krastorio 2 - Air Purifier Helper' and/or 'Krastorio 2 - Air Purifier':

The mod Krastorio 2 - air purifier helper (2.0.5) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event kr-air-purifier-helper::on_object_destroyed (ID 178)
Unknown item name: kr-used-pollution-filter
stack traceback:
    [C]: in function 'create_entity'
    __kr-air-purifier-helper__/control.lua:196: in function 'try_to_take_out_used_filters'
    __kr-air-purifier-helper__/control.lua:232: in function '?'
    __kr-air-purifier-helper__/control.lua:248: in function <__kr-air-purifier-helper__/control.lua:245>

Rolling kry_stdlib back to 2.0.9 restored functionality.

I figured it out. There is no such thing as kr-used-pollution-filter in the air purifier mod that the helper mod works with. There is, however, a used-pollution-filter. Removing the first three characters in a single line of a single file in the helper mod made everything work again. :facepalm:

The REAL question is, of course, how the heck the helper mod has been working just fine for over a month with that mistake in it. Go figure.

it's a piece of code that triggers in the rare chance that there is no construction robot nearby for immediate pickup, the purifier fork is to blame, krastorio 2 added prefixes to all it's things and the filter fork just hasn't bothered yet, i can remedy this somewhat on my end but ultimately that mod is to blame.

Ah. Thanks for the correction and explanation. Is it possible to check for both, so updating the purifier fork won't trigger the problem with your mod?

i already did that right afterwards ;)