Adaptive history autofill candidates are basically fixed url, but if user’s input starts with URI scheme, the autofill target will be full url.

https://hg.mozilla.org/mozilla-central/rev/4ccd82ad4423

STR for QA

1. Set browser.urlbar.autoFill.adaptiveHistory.enabled to true
2. Open a new tab and visit https://www.nytimes.com/section/health
3. Open a new tab and close the one from the previous step
4. Type h in the urlbar and pick the result with the URL from step 2
5. Open a new tab and close the one from the previous step
6. Type h in the urlbar
7. Verify that the URL from step 2 does not autofill

Basically we want to make sure that when you create some adaptive history with a search string like "h", "ht", "htt", etc. but the domain name of the URL does not start with "h", the URL should not be autofilled by adaptive history. In the STR above, adaptive history is created with "h" because "h" matches "health", but the URL domain name "nytimes.com" does not start with "h", and therefore the URL shouldn't be autofilled.

Thank you for providing the steps for testing Drew.
The issue is verified fixed in the latest Fx103.0a1 on Windows 10 and Ubuntu 20.04. There is no autofill for the letter 'h'.