I added description in comment in every cell containing abbreviations full text.
A backlink is a backtrace link from one note to other note when 2nd note is linking to the first note.
I think it's non-sense, I can't explain that in simple words 
, let me try in an example:
If "Note1" has link to "Note2", "Note2" should have automatic link (called backlink) to "Note1".
Check this request for Backlinks feature.
BTW, since I mention "Backlink" thread in this post, you'll notice that this thread will be backlinked there under first post automatically. This is a nice feature in this discourse forums.
Anyway, I guess if you have no clue on something, it's not important to you at all and you can evaluate it as 0.
0 is just my personal rating since I don't or plan to have it. But for you, you can put as 3 since you have it and planning to use it for Joplin. Bottom line, it's personal evaluation about your personal needs. Calculations will sum up the importance of every feature according to community needs.
Thanks for noticing this. I corrected it.