I can only tell you my experiences as a parent.
My older daugher is 10. This year, she brought home papers in which she had to identify things like the simple subject, the complete subject, the simple predicate, the complete predicate, etc. She also had exercises last year on whether something was a predicate nominiative or predicate adjective. (Personally, I find these rather pointless.)
However, I was lucky enough to spend a good amount of time in her "language arts" classes last year (as a guest editor) and found that the emphasis is in coherent writing, a logical flow to the writing, etc. The students would do peer editing for things like capitalization, puncturation, and subject/verb agreement. Then final drafts are given to the teacher who includes corrections on the mechanics of grammar as well as the content of the essay. If several students seem to make the same type of mistake, the teacher would review - for example, rules about capitalization.
I haven't yet observed things like "None always takes a singular verb" or "Make the verb agree with last subject when you have a compound subject joined by 'or' " so I don't know if that is past, or future, or simply assumed and corrected as writing pieces are turned in.
However, my daughter was easily able to recite when you use "I" or "me" yesterday when someone (not me!) asked her about it.
I've been impressed with the teaching so far - the emphasis has been on being able to clearly communicate your ideas, but it doesn't allow for sloppy mechanics in fnal versions either.