Arch Linux

Technically this is correct... The inkscape package has an optional dependency on python-lxml, that has on optional dependency on python-cssselect.

Okay, you're right: Strictly spoken, inkscape can work without python-cssselect. However, almost every extension requires python-cssselect (at least every extension I tried). Because this affects not only some exotic third-party-extensions but also the majority of the default-extensions, I would suggest to mark python-cssselect as a required dependency. Otherwise, many users will come to the conclusion that the package inkscape 1.2 is broken on Arch, because it is not obvious to track down two levels of optional dependencies.

Extensions shipped with Inkscape have a set of python requirements which should be considered non-optional:

https://gitlab.com/inkscape/extensions/-/jobs/2481704849/artifacts/browse/public/

Without these you will loose jpeg/tiff/webp export, most python extensions which look at svg styles, and most other shipped extensions that aren't super basic.

There are a few other modules which are used by second order functions, such as python-requests, python-appdirs, python-cachecontrol[filecache], gtk-gir, which are used by the extension manager and clipart importer functions.

As an Inkscape extension author I highly recommend to provide the dependencies mentioned by @doctormo in the package. Or at least provide an Inkscape extension subsystem package containing the required dependencies.

For Inkscape users, especially in science, extensions are a crucial part of the application. They should run out of the box as they do on all other os's.

I would expect all functionality of the package shipped with Arch to work out of the box. So, please consider having python extensions needed for this marked as required dependencies.

The situation with python-cssselect is especially problematic since nobody could imagine that they would need to install an optional dependency of an optional dependency in order to have basic functionality work.

At the very least, you could mention python-cssselect as a (direct) optional dependency.

Required dependency should not be necessary IMHO, I used Inkscape extensively for quite some time without even noticing.
Having it listed as optional dependency would be very helpful though. The only way to find out what is happening is by reading the python stack trace.
Ideally Inkscape would provide a pretty information message instead of just dumping python errors into a text field.

Edit:
Wait so with this "fix" we are now forced to install the 34 MB python-numpy package?

This is still an issue with 1.2.1-1

Dupe  FS#74985   FS#75436 

FWIW, Both Fedora [1] and Debian [2] have tweaked their python-cssselect deps recently. An optdep might be warranted.

[1] https://src.fedoraproject.org/rpms/inkscape/c/39c6c1b8
[2] https://salsa.debian.org/multimedia-team/inkscape/-/commit/890aed02

1. Open inkscape
2. Click on Extensions
3. Click on "Manage Extensions..."

Boom.
*python-cssselect* needs to be added as dependency of *inkscape*