“Missing autofillHints attribute”

Perhaps you are using an EditText. autofillHints is used in API 26 and above for filling empty EditTexts and it’s actually suggesting which type of content should be placed in there.

Just add :

android:autofillHints="username" // the type of content you want

To your EditText and warning will disappear.

You do this using the new android:autofillHints attribute to tell
autofill what type of content you expect, and
android:importantForAutofill to tell autofill which views you want (or
do not want) to be filled.

Read: https://medium.com/@bherbst/getting-androids-autofill-to-work-for-you-21435debea1

And this: https://developer.android.com/guide/topics/text/autofill-services

Edit:

You can however set:

android:importantForAutofill="no"

To the component to tell it is not important to fill and get rid of the error.