These translations work when the pointer is in the value window or if the resource keyboardFocusPolicy is set to Explicit, which you do by putting a line like the following into the file .Xdefaults in your home directory.
xtme*keyboardFocusPolicy: Explicit

Action Translation Description
save Alt-s Writes current file to disk
save-as   Prompts user for a new name, then writes file
quit Alt-q Exits, prompting for confirmation if file changed.
cut Alt-x Detaches a subtree, remembering it
copy Alt-c Remembers a subtree for later paste
paste Alt-v Places a cut or copied subtree into metadata
clear   Removes the text belonging to a subtree
duplicate Alt-d Makes and places a copy of the current element
swap Alt-grave Switches the order of the current subtree with the preceding sibling
prune   Deletes all subtrees that do not contain text
add-all Alt-a Adds all possible children to the current node
help Alt-h Opens element help window
list-home Alt-KP_7 Selects the root node of the tree
list-up Alt-KP_8 Selects the next visible node upward in the list
list-down Alt-KP_2 Selects the next visible node downward in the list
list-pageup Alt-KP_9 Scrolls the list down one screenfull
list-pagedown Alt-KP_3 Scrolls the list up one screenfull
collapse Alt-Subtract Hides one more level of the whole tree
expand Alt-Add Shows one more level of the whole tree
hide Alt-KP_4 Hides children of the current element
show Alt-KP_6 Shows children of the current node