As of right now there is no entry to configure a shortcut for Filter > Threshold.
Git commit a0542ec279e893bfe0adcabef0b3b14702d4fa07 by Boudewijn Rempt. Committed on 25/09/2018 at 07:20. Pushed by rempt into branch 'master'. Add an action for the threshold filter M +0 -1 krita/krita.action M +4 -0 plugins/filters/threshold/CMakeLists.txt A +18 -0 plugins/filters/threshold/threshold.action https://commits.kde.org/krita/a0542ec279e893bfe0adcabef0b3b14702d4fa07
Git commit e1ec23dd6a588270469e54e8f9a7d2d9d3e84015 by Boudewijn Rempt. Committed on 25/09/2018 at 07:25. Pushed by rempt into branch 'krita/4.1'. Add an action for the threshold filter M +0 -1 krita/krita.action M +4 -0 plugins/filters/threshold/CMakeLists.txt A +18 -0 plugins/filters/threshold/threshold.action https://commits.kde.org/krita/e1ec23dd6a588270469e54e8f9a7d2d9d3e84015