Here is a list of all documented namespace members with links to the namespaces they belong to:

Key_Codeinput : IBus
Key_Henkan : IBus
Key_Henkan_Mode : IBus
Key_Hiragana : IBus
Key_Hiragana_Katakana : IBus
Key_Kanji : IBus
Key_Katakana : IBus
Key_Muhenkan : IBus
Key_Multi_key : IBus
Key_Romaji : IBus
Keysym : IBus