Prior to conkeror 1.0.3, key-kill-mode does not work on gecko >= 25 (it will cause Conkeror to not respond to key presses) but still works on Pale Moon (which is a fork of Gecko 24 despite having a 25.x version number).
Key-kill-mode is a generic page-mode for blocking keyup and keydown events, for example on websites that bind keys normally used by Conkeror. To use it, load the module, and then add tests so that it will be enabled on your problem sites. For example:
require("key-kill"); key_kill_mode.test.push(build_url_regexp($domain = "github")); key_kill_mode.test.push(/\/\/.*slashdot\.org\//);
Another way to use key-kill is to enable it for all sites, then use QuoteMode when you want to pass keystrokes through to a particular page:
require("key-kill"); key_kill_mode.test.push(/\/\/.*\//); //regexp matches all sites
As of Conkeror 1.0.3, there is also a new option, which causes key-kill to apply to text input fields:
key_kill_input_fields = true;