sed
is not a parameter, that’s a unix command line tool which you can use in a Script (https://www.gnu.org/software/sed/manual/sed.txt)
If you’re not familiar with scripting I’d suggest you to rather use a step (like the Change value in file
one), or just modify the file and do a simple copy/move like I described here: How change package name with help Bitrise? - #4 by viktorbenei
I’d also suggest you to check this guide, to see how you can experiment with your config on your Mac / Linux machine: