Firefox 77 won't connect to non-domain address bar entries with periods anymore

Mozilla plans to change the processing of address bar entries with periods (dots) that are not domain names when it releases Firefox 77. Current versions of Firefox attempt to connect to entries with periods when they are entered in the address bar of the browser. If you enter a phrase like "my.bat" or "console.log", you will get a "Hmm. We’re having trouble finding that site." in Firefox currently as Firefox adds https:// in front of the query because it interprets the input as being a domain name that it should connect to. Note that Firefox interprets the phrase as a search term if it contains spaces.

The error is quite common for filename searches. I prepend ? to the query whenever I need to run a search phrase with a period to make Firefox search for the term instead of it attempting to connect to it as it considers the term a domain.

Starting in Firefox 77, Firefox uses a different logic when it comes to address bar entries that contain periods. Basically, if the term is not a domain, e.g. ghacks.net, it handles the term as a search. Means: Firefox maintains a list of top level domains (using the public suffix lists); if the typed string contains a period it checks it against that list to determine whether it should try to connect to it or run a search instead.

Firefox users who run the cutting edge Nightly version of the web browser will notice the change already. A search for console.log runs  a search in the latest version instead of connecting to it.

Administrators and users may add custom extensions, those not found in the public suffix listing, in the following way to force Firefox to connect to these sites:

1. Load about:config in the Firefox address bar.
2. Confirm that you will be careful.
3. Type browser.fixup.domainwhitelist.DOMAIN.EXTENSION
   1. Make sure you replace DOMAIN and EXTENSION with the values that you require, e.g.  browser.fixup.domainwhitelist.example.local
4. Make it a Boolean
5. Set its value to True.

You may also type the protocol when you need to access locally available sites

Firefox runs the search using the default search engine in that case. It is still possible to prepend ? to the query to make sure that Firefox runs a search for it. If you type ?ghacks.net, Firefox will run a search for the domain name instead of connecting to it.

Google Chrome, and other Chromium-based browsers, use the same technique to determine whether a user's input should be resolved or redirected to the search provider configured in the web browser.