Setup (one-time only)

sudo apt-get install exiftool

Just view metadata

exiftool "<filename>"

How to remove GeoTag

After getting path to image and filename:

cd mediawiki-1.27.4/images/<path>
sudo exiftool -overwrite_original -geotag= "<filename>"
cd ../../../maintenance
sudo php refreshImageMetadata.php --force --start="<filename>" --end="<filename>"

Then hit the URL for File:<filename>?action=purge in the frontend to make sure it's gone from the HTML.