from vim help:
tag command action in Normal mode
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|CTRL-W_CTRL-H| CTRL-W CTRL-H same as "CTRL-W h"
|CTRL-W_CTRL-J| CTRL-W CTRL-J same as "CTRL-W j"
|CTRL-W_CTRL-K| CTRL-W CTRL-K same as "CTRL-W k"
|CTRL-W_CTRL-L| CTRL-W CTRL-L same as "CTRL-W l"