I noticed something. Jimjar is a "spy". Who is he a spy for?
No, he
is a
spy. Not a
gnome, or a
commoner, or a
wolf, or a
beholder, but a
spy.
Check page 349 of Monster Manual

(the entry's not in the Basic Rules, I'm afraid)
Doesn't mean he's actually spying for somebody. (But he says a gambler and traveler, so yeah, he's spying

)
Take Mev Flintknapper as an illustration. He too is a deep gnome, but he too isn't given some generic svirfneblin stats. His stats aren't the
spy, but the
veteran.
The way to spot these MM references are if the word is in
bold, that's your cue to search the MM! (Check page 103 of OotA and page 350 of MM)
There's a difference between a gnome and a
gnome 