User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

when i create a .php file and try to open in firefox infinite loops occur opening tabs.

Actual results:

Im learning php as a beginner and when i save my file new.php in directory and later on try to open it through firefox. A loop occurs where multiple tabs are opening and I cant do nothing to stop it except exiting the firefox. I recorded the problem, im attaching the video file with this report

Expected results:

nothing that issue should be happened because opening a php file is just normal in all the other browser

This is a very old, known issue. Do not set Firefox as the default handler for php files.