Yes, that is the correct GItHub repo for Realm core issues. If you are signed into GitHub and create a new issue there is a template for Crash Reports: Sign in to GitHub · GitHub
You should see something similar to the following:
#### SDK and version
SDK : ? (Cocoa, Java, etc)
Version: ?
#### Observations
* How frequent do the crash occur?
* Does it happen in production or during dev/test?
* Can the crash be reproduced by you?
* Can you provide instructions for how we can reproduce it?
#### Crash log / stacktrace
<!-- The full stack trace. -->
#### Steps & Code to Reproduce
<!-- What steps/operations resulted in the crash? Please show any relevant code or steps that WE can
<!-- use to reproduce it. Even better is a full sample project that can reproduce the crash. -->
<!-- Code and files can be shared privately at help@realm.io if needed. -->