cydia is used for jailbroken iOS devices (iPhone, iPod touch, iPad, etc) in place of the official Apple App Store. Since these portable devices are not really on topic for SU, and Cydia doesn't do anything on a desktop system, I would like to suggest we remove the tag, which only has one closed question
If the tag is on one question, of few handful of question, you can always remove the tag from the question by editing it out.
Unused tags are automatically purged from the system,
(x)on the tag -> save changes...