Author of the blog post in question here. Let me clarify: they shouldn't be there because they're not OSI-approved, right? Just wanna get your point here.

(While I understand that BSL/SSPL lack certain liberties, I deemed it okay to mark them as "open source" for the purposes of this post.)

Not just lack of OSI approval, they're attempting to redefine the long accepted meaning of open source to include their new licenses. They want the goodwill of being "open source" without the obligations. The only sorts of licenses that have consistently been considered open source are either copyleft licenses like the GPL and do whatever the hell you want licenses like MIT and Apache. Do whatever you want... unless you're a big corporation... or unless you're part of a group the authors deem evil/immoral/unethical... etc. is a massive departure from the spirit of the term open source.

Makes sense! Will edit when I'm next to my laptop, I promise.

Thanks!

As you say in that section, "Open source licenses usually grant users permission to use open source software for any purpose." These source-available licenses (SSPL/BSL) are not open source exactly because of that: they place restrictions on users from using the software for any purpose. For example in the case of SSPL, it includes purposefully draconian language in the license that basically means that it can't be used freely to provide a "service". These kinds of "poison pills" obviously stop you from using the software for certain purposes.

> unless you're part of a group the authors deem evil/immoral/unethical.

What parts of the license mention that?

It is most likely in the "Additional Use Grant" which is tricky - because this additional use grant is distinct to each product licensed under the BSL. This additional use grant is also not that easy to find, since some licenses display it prominently, and others hide it under some additional legal fineprint[1,2].

From mariadb site: https://mariadb.com/bsl-faq-adopting/#limits

"Q: What are the usage limitations under BSL?

A: The usage is limited to non-production use, or production use within the limits of the “Additional Use Grant” defined by the vendor using BSL and specific to each BSL product."

[1] obvious Additional Use Grant for Couchbase, included clearly in https://blog.couchbase.com/couchbase-adopts-bsl-license/

[2] it is extremely difficult to find the Additional Use Grant for Mariadb products themselves. For MaxScale, which is their proxy product, it is buried in a file within the source code (which on the surface level might be a good place for it, but it's not very easy to find and I had to go through lots of legal print to get to it) : https://github.com/mariadb-corporation/MaxScale/blob/2.5/LIC... or https://github.com/mariadb-corporation/MaxScale/blob/6.3/LIC... depending on which version you are trying to use, etc.

I wasn't referring to the BSL specifically with that comment, I was referring to recent attempts to call licenses like the Hippocratic License "open source" despite being anything but. The BSL is just a different example of a similar thing.

> they shouldn't be there because they're not OSI-approved, right

No, they shouldn't be there because they aren't open source; OSI approval has nothing to do with it. (Though it's still a good indicator, similar to how FDA approval doesn't change whether/how well a drug works/is safe.)