Based on discussion on slack, @handrews suggested I post an issue relating to section 3.1 Keyword Behaviours.

I believe I understood the principals explained correctly, however I feel this may have been because I've been following developments and have a reasonable understanding. Regardless, I still had to read it 4 times to be sure it made sense.

I feel the order of these sections doesn't make sense.
Section 3.1.2 (Default Behaviors) is really hard to understand because the application isn't clear till you've read the introduction to keyword categories. Chainging the order of this so that 3.1.2 appears after keyword categories would make the application clearer.

Additionally, the phrase "extension keywords" is used, but it's never explained what this means.

Section 3.1.2 (Default Behaviors) also feels a little waffly. In my mind (and I assume other readers), I try to whittle down the paragraphs to a few main points that are trying to be communicated, and I can't seem to focus on the core concepts. Personally, I would suggest to consider making a list of things you want to communicate, then reduce anything which doesn't contribute to that aim.
Less is more in this case, I feel.

(Also, more paragraphs. The human brain's ability to comphrehend generally reduces after 4 lines of text. Most of the spec is pretty good with sticking to this, aiming for 3 lines!)