what is this hole inside bottom of window frame - help needed identifying

[SusanAnotherone]

hello,

I just had some new aluminium windows installed. On the inside of each of the frames, at the bottom (ie the part that is covered when the window is closed) there is a hole as per picture attached.

When I said to installer - what are these, surely they will just allow debris to get into the window frames. He said "they are the drainage holes of course !"

well, I have just spent a couple hours googling trying to establish if this is case. It seems that it is not, I think ! Im finding that there should be drainage holes on outside, at lowest point, to let water out, but Im not finding anything re this hole at top part of frame that I have.

Should they be there ? Perhaps there should be covers for them ?
any help much appreciated ...
thanks, Susan

[welsh brickie]

They are drainage holes, If you get a cup of water and fill them you will see the water appear outside