Man pages matching name tk_drawfocushighlight in section 3tk:

Tk_DrawFocusHighlight.3tk.en	debian 10 / tk8.6-doc
Tk_DrawFocusHighlight.3tk.en	debian 11 / tk8.6-doc
Tk_DrawFocusHighlight.3tk.en	debian 12 / tk8.6-doc