Man pages matching name tk_focusnext in section 3tk:

tk_focusNext.3tk.en	debian 10 / tk8.6-doc
tk_focusNext.3tk.en	debian 11 / tk8.6-doc
tk_focusNext.3tk.en	debian 12 / tk8.6-doc
tk_focusNext.3tk.en	debian 13 / tk8.6-doc
tk_focusNext.3tk.en	debian 13 / tk9.0-doc