Added Mods Gone

[Paradoxicles]

I downloaded an empty 1.16.5 modpack with only Optifine and added a few extra mods to it. However, when the modpack updated, the extra mods did not show up in the same mods folder. Where did the extra mods go? Another folder somewhere?

[JaariAtmc]

When the modpack updates, the mods folder is wiped and restored from the cache folder, which contains the new mods. Your old additions are just gone.