What is <<>> triggering, and how can I turn it off?

This morning was working on a draft of something where I needed <<>> in several places. Drafts activated some AI and turned that into a grammar exercise? Which is kinda cool because I am an ESL teacher? But also the grammar exercise was not really good, and - more importantly - not what I was trying to get done. I needed to put <<>> in my text and I didn’t want to trigger anything.
A. What did it do?
B. How did it decide what to do?
C. How can I turn it off?

Thanks!

There’s no AI involved. Typing << is one of several auto-complete triggers that opens a drop-down of suggestions. In the case of << is a shorthand for inserting content from other drafts (e.g. if you keep a snippet library you can easily insert the text of other drafts in the current one - this is a companion to the use of [[ to build links to other drafts).

More details on auto-complete in the User Guide

Auto-complete definitions are a feature of specific syntax definitions. There’s not a way to toggle them off and on…but you can just ignore the drop-down and keep typing or hit the escape key to dismiss it. Or you can use a syntax highlighting definition that does not support auto-complete, like “Plain Text” for the draft. This feature is only in the three “Markdown” syntaxes.