Per T153334, the consensus seems to be that the best way forward is to implement Unicode section IDs and percent-encoded fragments in MediaWiki URLs. For backwards-compatibility with existing saved URLs, we would add empty span tags with the old dot-encoded section IDs.
We already know that this implementation works with all current browsers, but we need to see how far back the support goes. Test percent-encoded fragments and Unicode section IDs (i.e. anchors) on all available browser versions until it is determined which version of each is the oldest to support this implementation. This should allow you to answer the following questions:
- What is the oldest version of Firefox to support this implementation?
- Internet Explorer?
- Mobile Safari?
- Chrome Mobile?
- Android Web Browser?
Here is a test page: https://kaldari.github.io/scratchpad/unicode-fragment.html. Browser support should be considered passing if all 3 test cases pass, i.e. all 3 links create a red "selected" arrow next to the proper section ID.
Please use a bifurcated search to efficiently narrow in on the oldest version with support, i.e. if there are 30 available version of Firefox to test on, it should take no more than 5 tests. (Log base 2 of 30 = ~4.9.)