You can also reverse engineer and modify closed source programs (see mods for games). Weights are like compiled version of source data.

Not legally. That's the difference.

Sure you can. It's often legally protected activity. You're just limited to distributing your modifications without the original work.

For some games maybe, but software often has a clause forbidding reverse engineering

ChatGPT says that such clauses are typically void in the EU, though they may apply in some cases in the US. Even in the US, the triennial DMCA rule-making has granted broader exemptions for good-faith security research every cycle since 2016.

https://chatgpt.com/share/6838c070-705c-8005-9a88-83c9a5550a...

Finetuning isn't reverse engineering. Finetuning is a standard supported workflow for these models.

Also, the "redistribute" part is key here.

> Finetuning isn't reverse engineering

Fully agree, it isn't. Reverse engineering isn't necessary for modifying compiled program behaviour, so comparing it to finetuning is not applicable. Finetuning applied to program domain would be more like adding plugins or patching in some compiled routines. Reverse-engineering applied to models would be like extracting source documents from weights.

> Finetuning is a standard supported workflow for these models.

Yes, so is adding mods for some games, just put your files in a designated folder and game automatically picks it up and does required modifications.

> Also, the "redistribute" part is key here.

It is not. Redistributability and being open source is orthogonal. You can have a source for a program and not be able to redistribute source or program, or you can redistribute a compiled program, but not have it's source (freeware).