Would it be better if wikimedia on upload just generate a warning "svg contains <a> tag" + an option to enable custom filter?
I think svg upload is responsibility of wikimedia admin\owner, not wikimedia developer.

sorry, just got notiffication about commit

don't know where I should comment (here or T123071), so sorry if it is wrong

edited,
please see T122653

sorry I put incomplete info, here the example:
The svg below is uploadable, but it shouldn't (?) as well as javascript shouldn't be allowed.

<svg>
  <a href="http://example.com"><circle cx="50" cy="50" r="40"/></a>
</svg>

The good case with relative link to the wiki (it is hightly useful to have for exported block diagrams)

<svg>
  <a href="my_local_link"><circle cx="50" cy="50" r="40"/></a>
</svg>

Please leave the ability to have local links in the svg. We use it for documents exported from Visio. It is the only way we can integrate those diagrams with wikimedia!
Thanks