I've only recently been reading about cache manifest and how it's type must be served as text/cache-manifest. Seeing this, I thought this being possible might might be a reasonable assumption:
<html manifest="data:text/cache-manifest;base64,...">
In the same way you can use it for text/html, application/pdf, image/..., etc. From initial experimentation, it seems to fail, plus this validator doesn't like it.
Could this work? Have I gone wrong elsewhere? Could it be embedded any other way? Thanks!
Well, it seems like some others beat me to the point, here:
Note: the manifest file is subject to the same-origin rule, in that you can’t point the manifest attribute to something like http://simpleapp.com/self.manifest. Equally, you can’t base64 encode the manifest file as some people have asked in the comments – that would be really awesome!