There is a simple keyboard shortcut, if you have copied formatted text and want to paste it into the ফায়ারফক্স browser as unformatted text.
To paste the text as unformatted plain text into ফায়ারফক্স ব্রাউজার, press the following keys:
Ctrl + পরিবর্তন + V
No extra plugins are required. This was tested in Firefox 52 on উইন্ডোজ 10. If this works in a different Firefox version or does not work in a specific Firefox version on various platforms let us and other users know in the comments section below.