It’s part of a custom modifier layer I implement using AutoHotKey. The layer is activated by holding caps and I have bound various keys for easy access (e.g. hjkl arrows). I bind caps+x to delete and also take into account ctrl/alt/shift modifiers.
So my frequently used shift+caps+x → shift+del mapping to permanently delete files doesn’t work on the X1 
I’m hoping when Framework releases the EC firmware source that I can implement this directly on the keyboard firmware!