Inquiry on "removing accts" in firefox app

Does the app really removes the main acct that is setup on my tablet? Last year, i had a wifi app that needed to access/remove acct on my phone..the next thing it did was physically locking me out of phone, wiping all data! So now iam cautious when an app says it might want to remove accts..even with a legitamite browser like firefox. Iam in need of a good browser, since now i use junky ones like 5G browser and Angel browser apps