"Torque to Yield " Bolts ....?

I have seen this before .....which I consider a funny image because for the bolt to 'yield' as compared to strech pretty much meant " Torque till they Break " .... but assuming they are not an oxymoronic joke.... what exactly are they ? I have read that Rolls Royce used "waisted" bolts... where the shaft between the threads and the bolt cap was slightly less diameter than ( the diameter measured between the bottoms of the threads ) ... and that they did not reuse them . And that they used shorter length of threaded shaft than others... This makes sense to me because it gives a longer area in which that strech can occur... and the longer the bolt the less (later not wanted) fatigue stretch occurs... in other words ... a longer bolt... torqued the same as a shorter one will keep more pressure on the item .