\\[riffle-scroll-other-window] Scroll contents one line
\\[riffle-scroll-other-window-down] Scroll contents one line
\\[riffle-summary-to-contents] Concatenate all contents
+\\[howm-view-summary-next-section] Next file (Skip items in the same file)
+\\[howm-view-summary-previous-section] Previous file (Skip items in the same file)
\\[howm-view-filter-uniq] Remove duplication of same file
\\[howm-view-summary-shell-command] Execute command in inferior shell