Internationalization support for command descriptions?

Internationalization support for command descriptions?

I'm introducing internationalization to my extension. I just tried the
following:
"commands": {
"nextVideo": {
"suggested_key": { "default": "Ctrl+Shift+Right" },
"description": "__MSG_nextVideoCommandDescription__"
},
"previousVideo": {
"suggested_key": { "default": "Ctrl+Shift+Left" },
"description": "__MSG_previousVideoCommandDescription__"
},
"toggleVideo": {
"suggested_key": { "default": "Ctrl+Shift+Up" },
"description": "__MSG_toggleVideoCommandDescription__"
},
"_execute_browser_action": {
"suggested_key": { "default": "Ctrl+Shift+Down" }
}
}
but the description values are interpreted literally. All other instances
of referencing messages.json in _locales work as expected.
Is this a bug?