Extensions can be mutually exclusive, but normally won't be.
I was talking specifically about options. Say extension "a" adds
":a" for a command and extension "b" adds ":b" for the same command.
Obviously, the script can use both
command ":a"
and
command ":b"
But can I use
command ":a" ":b"
?
Again, that depends. If:
(a) The interpreter supports both extensions.
(b) Both are listed in the require clause.
(c) Both extensions can be used at the same time.
Then the answer is "yes". Isn't this obvious?
Ned