Source-available is meaningless
keygen.sh
keygen.sh
You can argue all you want about the nomenclature and OSS side of source available, but I object strongly to the headline that it's meaningless. It's not. It's just "not open source".
But "source available", english-wise, sounds like you can only read it.
This pushes some to avoid the term and say open source since that's much closer to their what the license does, even if they are not exactly open source.
The argument is that "fair source" would be a much clearer term for most of the "source available with extra freedoms" stuff, and I agree.
It's not far from meaningless. The issue is you have no real way of knowing what relationship the source they made available has to the binary you are running.
If you are somehow guaranteed that the binary was derived from the source, then yes it isn't meaningless. It's not "open source", but you get many of the benefits of open source. Notably absent are the freedom to modify / improve and the ability to maintain it should they decline to do so.
One way to guarantee it corresponds to the binary you have would be to provide the source, plus reproducible build instructions, plus ensure all the tools and libraries needed to build it are available under the same conditions.
Without that it's just a promise, and worse one you even can't "trust but verify". That's pretty meaningless.