Plugin Manager in Core: Part 2-D (distinguish between critical & non-critical)

As it stands, the Plugin Manager doesn't really distinguish between a critical update and a non-critical update with anything more than a background color applied to certain rows. This is bad for both blind and colorblind site administrators, and needs to be fixed. We'll discuss ways to improve this right after the parent issue #395474: Plugin Manager in Core: Part 2 (integration with update status) gets committed.

It the parent issue, Everett was quick to point out that [with a screenreader]

There is colour (red) being used to communicate information that is not available in semantic markup. This information needs to be available semantically. Two suggestions for doing this are:
A. Sort the table by type (security, unsupported, etc.) and use a row to communicate where one section starts.
B. (Recommended) Provide some form of language e.g. "(Security)" and hide it off screen using a similar method to that recommended by w3c wcag 2.0 for links at http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/C7 . An issue discussing the best method of hiding text off screen in Drupal is being discussed at http://drupal.org/node/473396#comment-1810228

There was also a suggestion to theme the table's critical update rows into one div, and the non-critical rows into a second div right below it.