[O] "Special Properties" when matching for Properties in a search

[Gustav Wikström]

Hi list!

When matching for tags and properties using C-c / m there is the
option to match for Special Properties. Is there a complete list of
these special properties somewhere?

I was thinking that "7.2 Special Properties" in the manual would be
that list, but then noticed a property possible to use for searches,
but not available in that list (the LEVEL-property). Is that property
just missing from there?

/Gustav