Damage to oven glass needs assessment, even when it appears small. Heat and mechanical stresses make an improvised cosmetic repair inappropriate.
What the observation means
A chip, crack and removable surface deposit can look different; inspect only while cool and without applying pressure. Do not use the appliance to see whether the damage spreads. The complete door assembly may have model-specific glass layers and orientation requirements.
A useful next step
Stop using the oven and seek a compatible repair assessment. Keep the model reference and an existing clear photograph if useful. Do not fill the chip with adhesive, tape the pane or replace it with ordinary glass cut to the same size.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.