/usr/share/gnome-shell/extensions/ is in gnome-shell-extension-weather 0~20151125.gitccaa1eb-1~deb8u1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/OpenWeather.png
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/convenience.js
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/extension.js
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/forecast_io.js
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/metadata.json
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/openweathermap_org.js
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/prefs.js
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/stylesheet.css
/usr/share/gnome-shell/extensions/openweather-extension@jenslody.de/weather-settings.ui