New UI look lost old firefox uniqueness

[Lahiru_nim]

can this round corners makes more square 

[Agentvirtuel]

Bonjour

How can I remove the rounded corners in Firefox?
https://support.mozilla.org/en-US/questions/1607334

[dftf]

@Lahiru_nim until late November this year, this change will undo the round:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

Longer-term (until next September) you could move to the 'ESR' 153.5 version:
https://www.firefox.com/download/all/desktop-esr/