At https://libraryupgrader2.wmflabs.org/library, there are several non-php packages such as php extensions or php itself listed.
Clicking on these results in a 500 Internal Server Error: for example for the curl extension: https://libraryupgrader2.wmflabs.org/library/composer/ext-curl.
You'd expect to see an overview like for https://libraryupgrader2.wmflabs.org/library/composer/wikimedia/at-ease, where all the repositories using it are listed.
This is less useful for php itself, but for php extensions, it's quite useful.
Bonus: the overview mentioned above seems to have a broken title. All it lists is - libup. I'd imagine it should say something like composer: wikimedia/at-ease - libup, like the H1 element.