Autofill to Auto-Type

The autofill information should be saved in Auto-Type.

I think that this string field is a place to
store information related to entry (example: e-mail),
not about autofill.

I think Auto-Type field is the best place
to store autofill information.

(From email)

Start by tracing where autofill information, the string field, and Auto-Type data are currently stored and consumed in the Android application. Clarify how existing entries should be migrated or represented, then verify that autofill still works while the information is stored in Auto-Type rather than the string field.

Written by the indexing model from the issue text.