UPDATE: 

I got this solved by moving my extension to folder stated in Inkscape->Edit->Preferences->System->User extensions. Previously I had it in same folder with default Inkscape extensions.

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Hi, 

I have latest 1.0 (4035a4fb49, 2020-05-01). I have custom python extension which contains "import png". I have installed pypng module as global python3 install and set in preferences.xml:

<group

id="extensions"

python-interpreter="/usr/bin/python3"

When I try to run extension in Inkscape it complaing that module png is not found. But running in command prompt: "/ust/bin/python3" and in python shell "import png" works fine. 

What could cause Inkscape to not have same installed packages? Clearly python interpreter value is read by Inkscape as I tested with python-interpreter="/usr/bin/python4" and it fails completely to start extensions.

Any suggestions?

Thanks in advance!

Great! I think I've seen this question before, somewhere. Glad it's solved.