While the exact contents can vary depending on the version, an IPA (iOS App Store Package) from this source generally includes:
: The specific features of Repo4Tweak can vary, but such apps typically offer a range of tweaks and modifications. These can include customization options for the user interface, enhancements to system performance, or additional functionality not available in the stock iOS experience.
AltStore is widely considered the safest and most user-friendly way to install IPA files. It uses your own Apple ID to "sign" the apps, making the phone think you are a developer testing your own software. No jailbreak required; very reliable.
portatiilshop/repoipa: A collection of IPA files from ... - GitHub
You will need to sign the app with your Apple ID. This tells iOS that the app is "trusted" by you.