5 - Lots of profiling, make it faster!
6 - Plugins for major CMSes (very tricky issue)
9 - Make URI validation routines tighter (especially mailto)
10 - More extensive URI filtering schemes
11 - Allow for background-image and list-style-image (see above)
12 - Distinguish between different types of URIs, for instance, a mailto URI
13 in IMG SRC is nonsensical
14 - Error logging for filtering/cleanup procedures
17 - Add various "levels" of cleaning
18 - Related: Allow strict (X)HTML
21 - Additional support for poorly written HTML
22 - Implement all non-essential attribute transforms
23 - Microsoft Word HTML cleaning (i.e. MsoNormal)
26 - Formatters for plaintext
27 - Auto-paragraphing (be sure to leverage fact that we know when things
28 shouldn't be paragraphed, such as lists and tables).
33 - Extended HTML capabilities based on namespacing and tag transforms
34 - Hooks for adding custom processors to custom namespaced tags and
35 attributes, offer default implementation
36 - Lots of documentation and samples
38 Unknown release (on a scratch-an-itch basis)
39 - Silently drop content inbetween SCRIPT tags (can be generalized to allow
40 specification of elements that, when detected as foreign, trigger removal
41 of children, although unbalanced tags could wreck havoc (or at least delete
42 the rest of the document)).
43 - Fixes for Firefox's inability to handle COL alignment props (Bug 915)
44 - Automatically add non-breaking spaces to empty table cells when
45 empty-cells:show is applied to have compatibility with Internet Explorer
46 - Non-lossy dumb alternate character encoding transformations, achieved by
47 numerically encoding all non-ASCII characters
48 - Semi-lossy dumb alternate character encoding transformations, achieved by
49 encoding all characters that have string entity equivalents
52 - Non-lossy smart alternate character encoding transformations
53 - Pretty-printing HTML, users can use Tidy on the output on entire page