While switching tools from php6.5 to the new 2020 cluster and php7.3, I noticed an inconsistency.

For many tools, I include a JS file in index.html like "./main.js".

This always worked fine, but for tools that I switched to 2020/7.3, the URL (example)

• https://tools.wmflabs.org/magnustools tries to load https://tools.wmflabs.org/main.js (resulting in an error)
• https://tools.wmflabs.org/magnustools/ tries to load https://tools.wmflabs.org/magnustools/main.js (as intended)

These used to work identically (in the second, correct way).

Would it be possible to restore the previous behaviour?