It is the power wire to the ECM. The wire itself doesn't have any "memory". The ECM does.
Turbo Tweak sells a Tune Saver that is wired in between the battery and ECM via that orange wire to provide power to the ECM if the battery goes dead, but the wire itself is only for dedicated power to the ECM. The ECM has to have power all the time or it will revert back to factory settings if you have done any tuning via powerlogger or scanmaster.
The car will not run if it's disconected.