Hi folks,
CyberTracker is a new mobile data collection app which supports ODK Central. It runs on Android and iOS, but there are also desktop emulators for PC and Mac. We are building out the documentation and samples here.
CyberTracker was developed for wildlife conservation which has uncommon requirements. For example, field rangers may not be literate or have other needs like GPS track timers. Nowadays it is a more general tool, which can collect data for multiple backends and allows for significant control over the form UI.
Customizations are typically done by adding columns to the form. If you work at the XlsForm level, then it is quite easy to try out. There are tutorials and demos.
We do not have support for all XlsForm features, but most field types and common cases work well. If you are interested in the source code, you can check it out here.
Note that we are not thinking of or recommending this as a replacement for Collect. However, if you find yourself needing more control for a specific form, then this is probably a better option that creating a custom app.
Feedback welcome, thank you!