See this reference: https://github.com/matplotlib/matplotlib/blob/6f635b41ff4941af640c75b4d9bf0e0955066114/doc/users/installing/index.rst?plain=1#L34C65-L34C65

In current docs, it points to https://matplotlib.org/devdocs/devel/dependencies.html#optional-dependencies which is an invalid page.

I think it should link to this file/section: https://github.com/matplotlib/matplotlib/blob/main/doc/users/installing/dependencies.rst#optional