Hello pnaecker, welcome to the community!
This is a very interesting discussion! Regarding on how to download the files/traces/data from your Shake, this page on our manual should cover everything you need: How to download your data — Instructions on Setting Up Your Raspberry Shake
The data format of the files is miniSEED (.mseed), and copying the data would be best done with scp protocol.
There is also the possibility of having cloud backup of the data, discussed in this thread here on the community: Cloud Backup
And, if needed, you can also download the data from the FDSNWS service, accessing the entire worldwide network of seismometers. All these options are covered in the download page of our manual.
To conclude, the Shake does not have an in-built alert capability, but our RSUDP software, developed by Raspberry Shake, does! You can find the full documentation here: rsudp 1.0.1 — rsudp documentation