Load the extension unpacked, grant it access to this page, then type in either box and pause. Use it to check underline placement before touching Gmail or WhatsApp — the second box is a plain contenteditable, which is the same shape as their editors without their framework fighting you.
Try: pls revert back on the informations i recieved — and paste
something with an emoji or a Devanagari word in the middle to confirm the underlines stay
aligned.