The one I have monitored intensely for years is:
Blockade-Runner
Decreases chance of being detected by enemy vessels.
Bitvalue: 2048
I don't see any percentage nor do I understand why it would be assumed that it is automatically +10% since chance of detection is - firstly - dependent on your fleet's visibility rating. As such, a single TP should be nearly undetectable travelling the oceans alone; and downright impossible if captained by a Blockade Runner. NOTE: Some leaders listed give 25% increase in traits.
UNFORTUNATELY, I can tell you from personal experience, that single TPs with block runner indeed are detected sometimes. But it is impossible for me to attribute odds to that. But I would never transport very valuable cargo like HQs and ARM on single TPs with that leader as their only protection.