|Just another Perl shrine|
> It is not valid html. (Yes, I know <readmore> isn't either.)
You seem to believe PM is allowing you to use HTML to compose nodes directly.
But in reality it's not less an artificial board-markup than BB-code is, just with far less of a learning curve for people knowing (old) HTML.
It's a markup which is stored raw in a database and for display it's filtered and rendered into (more or less) "valid" HTML.
Our options to deprecate old approved PM-markup are very tiny. It's our data-format, an XML dialect if you want. (just click on XML in the header to see how it looks like)
It's in use for 20 years already and old posts still need to be rendered.
You mentioned in another post that <font> might become deprecated and not displayable. That's not really an issue, because in that case we can still change the renderer to translate <font> to valid <span> , pretty much the same way we translate <c> tags into <code> tags.