He made a post about some future printers not being fully open source anymore. The post is here: https://blog.prusa3d.com/the-state-of-open-source-in-3d-printing-in-2023_76659/

These are the working points for their future license (not fully fleshed out):

• If you’re using some code or blueprints to bring software or hardware to market, the original code’s authorship must be clearly stated on the product or in the software. Additionally, deleting copyright information from headers and history from repositories is prohibited.
• The production of nearly exact 1:1 clones for commercial purposes is not allowed.
• License for manufacturing spare parts is valid for service, modification, or educational purposes.
• Upgrades and additional modifications based on original parts are allowed and welcome.
• Parts that can be considered consumables (e.g., thermistors, heater blocks, fans, printing plates, etc.) can be manufactured and sold commercially after the verification by the licensor based on the presentation of samples.
• If a product is labeled by the manufacturer as obsolete (or cannot be purchased or ordered for longer than 3 months), the non-commercial clause is automatically terminated if identical parts are no longer produced within the successor of the product or cannot be purchased separately.
• If the licensor ceases its activity, the non-commercial clause is terminated.

These terms are incompatible with open source.