TI actually L: I was wondering whether it was getting a bit crowded at the L2 "point" and how big a point it actually is, but it turns out that the various telescopes do not just orbit the sun but also orbit the L2 point. How they orbit something that's not actually there and so doesn't have any gravity is some kind of magic to do with gravitational wells or something.
They're only not there in the sense that a hilltop isn't there: Think of gravity like a contour map, with the Earth and Sun as holes of appropriate depth. L1, L2 and L3 are 'saddles'
[1], and L4 and L5 are ridges. If you place an object near L1, L2 or L3 it will tend to drift away, but if you put it in orbit around the point, you can keep it there with the occasional burst of thrust. That's why the JWST's lifetime is limited by its fuel supply; eventually it will run out and go wandering off into heliocentric orbit.
You'd expect the same to be true of L4 and L5, but it turns out the contour map is rotating (I dunno, it's in the hands of a car passenger who's a frequent perpetrator of terms like "other left" or something), and inertia pulls it back into place.
[1] In the horse rather than bicycle sense.