For the various forms of “Copy Message” operations in the Diagnostics Output dialog, the relevant messages lines are now copied to the system clipboard in two formats:

When pasting into Microsoft Word or Excel, both “unformatted” and “formatted” options appear in the menu; the formatted option presents the Line Numbers (if shown), Context, and Message in different columns. When pasting into a simple application which supports only text, like a text editor, only the unformatted plain text is pasted.