Your comments

The solved problem aside, I'd really like to "see" the line ending characters in some cases.

You can make a plugin that takes care of that to your likings.

1. The decision is yours. If you like an idea, vote it up. If you want an idea to become real, vote it up. If you think something is not useful at all (implementation would only waste time), vote it down. etc.

2. If you don't care about an idea/question, just leave it as it is.

3. You could've asked this in the forum since this question is not feedbak for the application itself, but since Jon only rarely takes a look at userecho it shouldn't be that fatal.

Your only possibility to parse values/arguments that are not specified in Sublime's key binding extension (like "$file") is to modify the command itself.
While it would be nice to have Sublime extend your (view's) settings in keybindings, build system etc. this can be done inside SublimeREPL. You should open a ticket there.

 The plugin looks good. However, this does not really allow adding a snipped to a package because the target machine would need your plugin installed as well and I hate plugin dependencies (well, everyone should).

I'd also like to be able to call `uuid.uuid4()` inside a snippet. Would allow me to actually create a snippet and not a plugin that does this.

 I'm all in for enhancements to the UI API.

 The up and down key bindings for search panels seem to be hard-coded and are not defined in the Default keymap.

My attempt with

   { "keys": ["alt+up"], "command": "move", "args": {"by": "lines", "forward": false}, "context": [
     {"key": "panel", "operand": "find"}, {"key": "panel_has_focus"}
   ] },
   { "keys": ["alt+down"], "command": "move", "args": {"by": "lines", "forward": true}, "context": [
     {"key": "panel", "operand": "find"}, {"key": "panel_has_focus"}
   ] },
   { "keys": ["up"], "command": "find_prev", "context": [
     {"key": "panel", "operand": "find"}, {"key": "panel_has_focus"}
   ] },
   { "keys": ["down"], "command": "find_next", "context": [
     {"key": "panel", "operand": "find"}, {"key": "panel_has_focus"}
   ] },

also does not work (neither with "find" nor "incremental_find").

Also not with

     {"key": "panel", "operator": "equal", "operand": "find"},
     {"key": "panel_has_focus", "operator": "equal", "operand": true}