Steps to reproduce the issue

While updating a test site from J3 to J4, I noticed an odd icon. The class is icon-play, which should result in a play button triangle. But it resolves to expand arrows, similar to https://fontawesome.com/icons/expand-arrows-alt?style=solid.

To see the icon, navigate to administrator/index.php?option=com_joomlaupdate&view=update&layout=finaliseconfirm. You don't need to actually run the update, just look at the buttons below the login form.

Expected result

A play icon, like in J3. For comparison:

Actual result

System information (as much as possible)

Mozilla Firefox, Joomla! 4.0-dev

Additional comments

It's not restricted to the update form, you can also just use something like <span class="icon-play"></span> somewhere on the site.