Yesterday I went through my website errors and found a mysterious error.
There were mysterious requests for siteinfo.xml.
First I thought maybe there is an invalid link for the file somewhere on the forum software, but later realized it was coming from the same place.
After investigating abit further I derived that it was the A9.com Toolbar that requested this file.
On the Toolbar there is a SiteInfo dropdown menu which can be defined by this file in your sites’ directories.
If you have a A9.com toolbar you can click on the SiteInfo menu for some shortcuts to other sites.
I think there would also be other toolbars using this feature as it is an open standard.
More information: