What is the difference between glyphs ending in .comb and .combsc?

Glyphs
#1

Hey guys,

I would like to know an explanation for the two glyphs .comb and .combsc? I attached some screenshots for the latter. I also would like to know why I have them duplicated 3 times and the third duplicate is greyed out? If you guys can simply the explanation, that would be lovely!

Thank you so much for your explanation! I am still learning!

#2

I can’t even upload the screenshots, it says error.

#3

Reading the Tutorials on diacritics is your best resource for a comprehensive explanation.

Here:

#4

It looks to me that adding the extension"sc" to “comb [combining]” means the glyph comes with small cap glyphs and is thus higher to accommodate them.