Hi @ChristineWk, great thought.

To make it easier and to have it go through faster, it would be great if you proposed a or a couple of better versions, then a PR can be made easily/faster if found to make sense.

Language Constant is:
COM_JOOMLAUPDATE_UPDATE_CONFIRM_BACKUP

example for CSS:

.com_joomlaupdate .form-check-input[type=checkbox] {
outline: medium solid var(--focus);
outline-offset: .2em;
}

We all are german and need help of a native speaker.
My suggestion is something like
"yes, I am aware that a backup is highly recommended before starting the backup"

Other checkboxes in list views have been improved in 5.1. #41400

Maybe the german needs adjusting, I don't know, but the english makes perfect sense to me (now that the checkbox is more visible)

Agree with instructions. English is clear, German is not @tecpromotion

But the issue of invisible check box remains. Other checkboxes are better now, but not this one. It has another class than the checkboxes in listviews.

@ChristineWk @chmst
https://github.com/joomlagerman/joomla/issues/new/choose

But the issue of invisible check box remains. Other checkboxes are better now, but not this one. It has another class than the checkboxes in listviews.

Don't forget that in the screenshot the checkbox is disabled. Its not enabled (and more visible) until you have selected a file

Text is more visible, but checkbox still isn't.
This would solve it:
Change:
--form-check-input-border: var(--border-width) solid var(--template-bg-dark-20);
to
--form-check-input-border: var(--border-width) solid var(--template-bg-dark-80);

I think that a more userfriendly solution would be:
Hide the second block until the user has selected a file, then make it visible.
Then it is not necessary to disable a text which for users looks like a bug and has no a11y contrast.

Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.

https://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html

I know that and did not label it as a11y issue.

has no a11y contrast.

sorry, i saw that so commented

The original issue is not about the text but about the checkbox that is barely visible. One of my customers called me some time ago with the same issue "can't update". Turned out he hadn't seen the checkbox.
Joomla 4

Joomla 5

Different css though:
.form-check-input { border: var(--border-width)solid var(--border-color); }
--border-color: #dee2e6;

The issue joomlagerman is outsourced and therefore treated separately.
Thanks for the suggestions about the checkbox.

I'm sorry it looks like i have closed this ticket here in the wrong tracker. Will reopen here and move my comment to the correct issue.