Application for adding an additional feature to the mod settings
and why is this needed?

for the sake of compatibility with other (animation) mods.

(If this can be done then write to me!)

How would only removing one arm during vanilla hands make it more compatible with other animation mods?

Compatible with hands in first person animation mods oh wait i will send screen shot

and

That looks like you didn't turn on Vanilla Hands in the settings.

Withot Vanilla Hands

with Vanilla Hands(look at the shadow i hold shield but this not visible)

Here with Vanilla Hands with double hands

Not sure why the shield wouldnt be visible. You can try the latest dev build, but otherwise this is just a plain incompatibility with whatever mod you are using there(looks like what I was working on but stopped because trainguy was also working on this).

i download working from (github) not discord server mod.
i can't find they server Unfortunately.

As I said, I used to work on exactly this(seeing the arm in firstperson https://github.com/tr7zw/AnimatedFirstPerson), but since trainguy is working on the same thing but better, I stopped.

Can i download that?
and this works with gradlew building process?

It's stuck on 1.19.2 or so and incomplete as I never finished that mod.

les'go i started that!
that pretty cool that i can say

Gonna close this. Once Trainguy finishes his mod, then it's time to look into that.