iOS has seen a lot of development in terms of hacking and infiltrating the system, although the activity is sinking, it hasn't stopped as the developer going under the name Sparky, who is responsible for the Meridan jailbreak for iOS 10, has released an early prototype of the OverCl0ck jailbreak, which is the first ever public jailbreak tool for the Apple Watch.
Sparkey notes that this is a project in very early stages and only supports watchOS 3. It may even only support specific Apple Watch models and not work properly with different sub-versions of watchOS. It's a project that's highly work-in-progress and it's only meant for developers who know what they are doing. To quote the developer "it barely works".
The jailbreak doesn't include a package manager like Cydia or Installer, nor does it include any code injection like Substrate or Substitute, which means that it's essentially useless for regular users who want to theme or tweak their devices. The developer has stated that if the project ever turns out to be something, he wouldn't mind coding a small package manager to get Cydia-like functionality for
If you really don't care about our warnings, or if you're an experienced developer, the tool can be downloaded from the link below.