The devdoc page building/target_platforms/target_platforms_updates.adoc#update-the-target-files is very confusing for someone who's just trying to get something added to TP. If build team insists on regular devs following this workflow / policy, it must be organized properly so as not to confuse average devs.
1) Checking if requirements is currently mirrored already should be very high up in the ToC of the page
2) Page should indicate that all of Mars is already duplicated, and does not need its own special folder with a build.xml
3) Page should then indicate if the IU you need is not in the 'mars' folder, it must have its own folder with a build.xml
4) Page should prioritize creation of the build.xml higher above making changes to the .target file
Basically, the entire page needs to be revisted and seen through the eyes of someone who hasn't made TP updates before. You need to direct the dev in what they need to do first, especially if you intend to keep linking this document