... do i have to say anything else besides the title?

Please, @MisterPeModder

I've upgraded the code to work with 1.20.4 and created a PR for it.

Could not test forge, because I only run fabric - but here are the files:

https://github.com/dfox288/ShulkerBoxTooltip/releases/tag/v4.0.8

An official version would be nice to publish it in modpacks.

Done ! Sorry for the very long wait and thanks agains @dfox288 for your contribution !