Despite being a PHP developer and Firefox user for a couple decades, I hadn't added a search of php.net to my Firefox search engine list until some months back. Now I can type @php<tab> and then enter a search to quickly look up PHP functions, classes, etc. To do so, go to about:preferences, click the "Search" tab, go to the "Additional search engines" section, and click "Add search engine". Set:
Name: php.net
URL: https://www.php.net/manual-lookup.php?pattern=%s
Keyword: @php
Click "Add Engine" and it will be available to use and help speed up PHP development.
It's possible that I had added something like this to a previous profile, as I created a new one when Firefox switched to the Quantum engine. But that was still almost a decade ago. And I think my work profile has been continuously used since 2010.