Right, there are many forks of the software, which is allowed under the AGPL licence.
Slic3r by Alessandro Ranellucci established the original open-source foundation.
Then PrusaSlicer forked from that -ok.
Then Orcaslicer forked from that -ok.
Then Bambu locked down it's fork - not ok, violation of the slic3r AGPL.
It's like..can I borrow your car? puts a bumper sticker on it, changes the locks, my car now.
Slic3r is licensed under the GNU Affero General Public License, version 3.
The GNU Affero General Public License (AGPL) is a strong copyleft, free software license designed to ensure source code remains open, even when software is run over a network. Based on GPLv3, it closes the "ASP loophole" by requiring companies that modify and offer software as a service (SaaS) to make the source code available to users.