Looks like it's explained here: https://github.com/charlotte-os/Catten/blob/main/License/cla...
Specifically, "Users may link this kernel with closed-source binary drivers, including static libraries, for personal, internal, or evaluation use without being required to disclose the source code of the proprietary driver.".
Ok, even Doug Crockford has mucked around with licensing before, so this is definitely a digression and not aimed at CharlotteOS which looks fascinating:
I wish there was a social stigma in Open Source/Free Software to doing anything other than just picking a bog standard license.
I mean, we have a social stigma even for OS developers about rolling your own crypto primitives. Even though it's the same very general domain, we know from experience that someone who isn't an active, experienced cryptographer would have close to a zero percent chance of getting it right.
If that's true, then it's even less likely that a programmer is going to make legally competent (or even legally relevant) decisions when writing their own open source compatible license, or modifying an existing license.
I guess technically the "clarification" of a bog standard license is outside of my critique. Even so, their clarification is shoe-horned right there in a parenthetical next to the "License" heading, making me itchy... :)