I just came across a video from 'bamcef' (not sure about their authenticity on all matters but still credible on a few ) and also tried ascertaining the truth with regards to use of janeo vs black thread that we see around the waists of children or even grown ups and they state that janeo was only for rajputs, brahmins and vaishyas and black thread was for shudras. There is no doubt about south west India that indeed it was used there for shudras but in North India, it was shocking to hear. Later on they changed arguments to say it was to cast away the evil eye or for dharan/nabhi stability. This is outrgeous. Here is the link for the video

https://www.youtube.com/watch?v=q4vaAtre5gY

another pdf talking about jat history for those who keep on defending brahmanism

http://shodhganga.inflibnet.ac.in/bi...hapter%201.pdf

see for yourself how they claim that they impregnated women after parshuram killed all kashtriyas and how jatts father are parshuram and lot and also how Al beruni mentions that in 11th century jatts were shudras. Same has been stated for 8th century as well .