of the formats (so far, html, html3, bbfr, and svg)

sometimes send them to external viewers and become confused if the
filename ends in '.php' (despite our correct content-type!)

C predecessor.

* Change canvas size
* Fix coordinate of label "Moo!"

script might be content-negotiated, renamed, symlinked, or otherwise
alised in URI-space.

lynx/elinks) and some alt="..." text so the validator does not complain.