You can just change the extension once they are downloaded. Then you will be able to unzip them.
Lesson
Export lesson
གྲོས་བསྟུན་འདི་བསྡམས་ཡོདཔ་ལས་ ལན་གསལ་བརྐྱབ་མི་ཚུགས་
You can just change the extension once they are downloaded. Then you will be able to unzip them.