hmmm... actually, now that I experimented a bit with this, it seems whenever I log into Gmail using Avast SafeBrowser, Avast is added to my Google Account as a third party app with full control (see attached .JPG).
Gmail has the following write-up regarding this:
Full account access
If you give a site or app full account access, it can see and change nearly all information in your Google Account. Full account access means a site or app can see and copy your information, edit or delete it, or create new information. Sites or apps with full access can’t change your password, delete your account, or use Google Pay to send, request and receive money.
I can log into Gmail with Internet Explorer, and IE is not shown in Gmail as a third party app with full account access.
Perhaps there is no difference and perfectly normal, but for some reason Avast is listed and IE is not?