In the software world "open source" has a well defined meaning: if a program is actually open source, you should be able to rebuild it youself from (guess what) the source code. Open weight models are not open source! They might share some of its characteristics, such as (for certain licenses) the ability to be used for commercial purposes, and have derived work generated from them However, without access to the actual training data they will never be open source. Not even close.

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