Gegenschein is a "faint brightening of the night sky" at the anti-solar point. A naked eye limiting magnitude of about 7.6 might enable an observer to make out gegenschein.
The Wikipedia article on gegenschein suggests that interplanetary dust at the Sun-Earth L2 point might be responsible for gegenschein.
The James Webb Space Telescope will also be at the Sun-Earth L2 point.
Does this imply that the same interplanetary dust that may be responsible for gegenschein will affect the JWST?