there are a lot of things which have been mentioned.......but thats it.........can we make a list of those things.......
1. why did voldy return back.......
2.aberforths goat experiments.....
3.some room caved in (mentioned in poa)
4.an axe in ror...in hbp......but i think it was the one used to finish of sir nick
so on.........i think jk wanted to tell us a lot but it was not related to main plot........ so they got chopped..........and ooh......grindelwald........and rons some family member who was a squib..............those sort of things....

Nikhill you are truly a HP Investigator, it's been awhile since I've read the books so I'm not that intune with the details. For #1 do you mean how come Voldy rose again in Book 6 or what? For #2 what expreiement was mentioned and is Aberforth Dumbeldore's brother? I can't remember who he is. Lastly for #3 when was the room being caved in mentioned in PoA, like what was going on? And do we know what room they're talking about?

I have one:

5. How come Harry was able to pull out Godric's sword in CoS?

thanks....for calling me investigator.... ^_^ .......any way..........voldy coming back???
in hbp ............dd shows a memory to harry in his penseive........... after voldy transformed .......the time people started fearing him....it is titled VOLDEMORTS REQUEST ......dd says that voldy came to ask for dada job ......but thats not the real reason he came.....i put a poll on this in quibler.....

in gof ......dd says that his brother(aberforth)......was given ministry warning or something ......it was told when he was trying to convince hagrid to do his job

in poa.....fred and george talk abt the room that caved in .....when they give him the map......also harry mentions to sirius this when he was searching for a place in practice dada.......

and thanks to you i remembered one more

dd says when trying to convince hagrid to do his job......he mentions that
6.he doesnt know whether his brother aberforth can read or not