Success Criterion 3.2.5 (Change on Request) says that the content must have a mode available which requires no automatic change of context for the functionality to be completed. All changes of context should be initiated by the user, or a mechanism is available to turn off any automated changes.
One possible issue with links is that they may open in a new window without warning, thus failing this Success Criterion. If a user is told the link opens in a new window, it is OK.
If HTML_CodeSniffer sees a link with a target of "_blank", it will check for the mention of "new window" in the link text. This should pass that test. Two links are provided with different capitalisation, to test the case-insensitivity of the link test.
Note that the "new window" mention has to be in the link text, since this is a AAA test, and thus Success Crterion 2.4.9 (Link Purpose: Link Only) also applies.
Note: This test must be performed at AAA level. By default, the bookmarklet will not show this message, as it defaults to AA level.