Documentation: Advertise pipx for program installation (PEP 668)

[amotl]

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Installing Python packages using pip, eventually contaminating the system Python installation, has been deprecated by default. The recommended installation method, at least as advertised by Debian, is to use pipx.

    If you wish to install a non-Debian packaged Python application,
    it may be easiest to use pipx install xyz, which will manage a
    virtual environment for you. Make sure you have pipx installed.

References

• Documentation: Recommend using pipx for installation (PEP 668) #443

Thanks, @bmunkholm.