It is probably an old markup variation of XML/HTML, best bet would be to probably make your own parser to convert the eve specific parts ie fontsize=14, to a more standard css style then assume the rest is html.
For example:
<loc>
<url=http://www.example.org/>
NEW EXAMPLE WEBSITE
</url>
</fontsize>
</loc>
Parse that into like:
<a href="https://www.example.org" style="fontsize: large;">NEW EXAMPLE WEBSITE </a>
That was my first approach, but the markup is not XML structure wise and can probably also not be directly parsed into a tree/XML DOM like structure. This makes all XML parsers useless. Some html parsers are forgiving enough to work to some degree.
The best I have so far is to make extensive use of regular expressions
What might work is to lex the raw string and then transform it such that it can be parsed as a tree.
e.g.
Step 1: on out-of-order </b> tag, reorder
<b><fontsize=14><i>Hello</b></fontsize></i>
^
Step 2: on out-of-order </b> tag, reorder
<b><fontsize=14><i>Hello</i></b></fontsize>
^
Result: What I'd call 'CCP XML-ish'
<b><fontsize=14><i>Hello</i></fontsize></b>
Step3: Now we have proper XML structure, convert to HTML
<b><font size="14"><i>Hello</i></font></b>
But for that I’d need to write a proper lexer and transformator