When writing the script by hand, you should include two lines here which say: set f to file of window 1, tell application "Finder" to move f to trash.  (This cannot be recorded as such.)

This is recorded as “extended copy with append to clipboard” because AppleScript refuses to compile “copy with append to clipboard”.

When writing the script by hand, the following two lines of script can be replaced with a single “set selection of window 1 to (grep substitution of <replacement pattern>)”.