Google Webmaster Central’s robots.txt analysis tool has been improved to recognize sitemap declarations and relative urls.

Google says that previous versions “weren’t aware of sitemaps at all, and understood only absolute URLs; anything else was reported as Syntax not understood.”

Improvements include :

• System now tells webmaster whether sitemap’s URL and scope are valid.
• Webmaster can also test against relative URLs with a lot less typing.
• Reporting is better : webmaster now alerted of multiple problems per line if they exist, unlike earlier versions which only reported the first problem encountered.

More information from the Google Webmaster Central Blog.