The current UI for the release notes UI is kind of dated. After upgrading a Mac to Tahoe, this seemed to make this more clear to me (screenshot below is in Sequoia)

• Some labels in the top portion could go away (Release Notes: label, maybe Software Update title)
• Release notes can take entire window width instead of having large margin of dead space
• We can do away with a box view, especially ours which uses some deprecated/old style

Without making any major drift in functionality offered, I think this window could be refined.

In discussion #2559 Peter posted a mockup which I think could be a nice improvement: