Font permissions

When embedding fonts there are four levels of font permissions, that is to say four levels of usability depending on how the font has been licensed. The four levels are...

Installable - the most permissive level. Allows the font to be embedded in the document and installed permanently on the guest computer.
Editable - Allows the font to be embedded in the document but only allows it to be used temporarily on the system.
Print and Preview - Allows the font to be embedded in the document but only for printing and viewing purposes.
Restricted - The font cannot be embedded in a document.

Apart from the warnings Xara shows you listing those fonts that will be embedded in your website, it is also possible to view their permissions levels by looking at the Document Info. Go to "File" > "Document Info...".

Document info dialog showing fonts together with their embedding permissions.