Why PKGBUILD welcome in github (commit c7bd151 (latest commit)) does not create same identical .zst package as archlinux repo endeavouros/welcome-3.34-1-any
You can run command
tar xvf welcome-3.34-1-any.pkg.tar.zst
for both files and compare the results.
The source code should be the same.
There can be e.g. different build date inside a dot file.