@vic@astrid sh is systemlinked to /bin/bash on most systems and it just tells bash to go into POSIXly (sucky) shell mode.
What bash has going for it is that it's free software that respects the 4 freedoms and is free software no matter where it is used; bash --version; GNU bash, version 5.2.37(1)-release (x86_64-pc-linux-gnu) Copyright (C) 2022 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.