Cydia Installer - Repo Sileo

was created by Jay Freeman (saurik) in 2008. For over a decade, it was the default package manager for almost every jailbreak.

If you have a jailbreak that supports both (like unc0ver or checkra1n), you can actually run Cydia and Sileo side-by-side. However, having two package managers write to the same APT database can cause . cydia installer repo sileo