I've been shelling out to tput to get terminal-specific escapes. (The tput command queries the terminfo database.) This is easy to do given the pipe access provided by lib_file_io.
Please feel free to appropriate code from the package manager. You'll need pkg⍙sh, pkg⍙utf_to_ucs (I believe that you can substitute 19⎕cr) and a call to ⎕fx to bind lib_file_io. Those'll give you a way to shell out any command. Then you can do, for example, ∊pkg⍙sh 'tput smso' and ∊pkg⍙sh 'tput rmso' to get the terminal-specific escape sequences to begin and end standout (i.e. reverse) mode. You can change the argument to tput to get any escape sequence that the terminfo database knows about the current terminal. A query for a nonexistent sequence returns empty. I also wrote a pgk⍙tput wrapper to degrade gracefully in the case that the underlying platform doesn't have the tput command. See man 1 tput for details and examples.
