Also by default Firefox can't make Addon that is up to the developer to make such Addon as they did for Chrome you should ask the Chrome addon developer to make on for Firefox as well. That is something you should use a link to make such request. https://support.mozilla.org/en-US/kb/file-bug-report-or-feature-request-mozilla

this post is addressed to the Firefox devs im not looking for a addon

If Mozilla were to add a clock to the (desktop) Firefox web browser, they would have done so long ago.

Something like this is what Extensions are for.

Here are some digital clock extensions where the time appears in the toolbar button (see screenshot):

Icon Clock (12/24-hour, custom colors)

Small Clock (12/24-hour, custom colors)

Minimal Digital Clock (12/24-hour, custom colors but only three digits)

Clock-hours or Clock-hours-12 with Clock-minutes (12/24-hour, two buttons, black or white text depending on theme)

Digital Clock (12/24-hour, white text on black)

CL0CK0 (24-hour, red text on black)

A digital clock as part of the browsers UI (To the right of the searchbar in my case) Chrome has a Addon for that sadly firefox does not. So id like to Request for you to add a digital clock to the Customize Firefox Page. The size of flexible space would do or slightly smaller and let us change collor and 24 or 12 hour please.

A flexible space can be very small or very large; most controls have a small fixed width. Could you share a screenshot of the clock you like, or a link to its page in the Chrome extension store?

More generally, Mozilla has a product suggestion site at https://connect.mozilla.org/. I think if you have time, it would be a good idea to post this request there to get into the current feedback stream. Use the "Ideas" section of the site.

And for now, an add-on similar to your Chrome add-on could tide you over.