Cannot add a suggestion for a greyed-out area in the Files / Files Changed tab

[electricjesus]

I can write a comment here fine:

or even in the black-background area above that (e.g. a non-change)

but sometimes i'd like to point out something on the grey area, too:

But as you can see, the comment box plus button doesn't even appear.

Also, is there a way to add suggestions that have line numbers as parameters e.g.:

[oliver-sentianse]

This is from last february. Github no idea why this is happening? It is preventing from reviewing these lines, it is weird, I can't see any rhyme or reason to the lines that are grayed out.

[nalbion]

In the GitHub Advanced Security video they're able to create a ````suggestion` with "Outside changed files" targeting line 16 of package.json in GitHub comments. I'd love to know how this is done.