@kropot wait, is it with or without the question mark?
@StroomAfwaarts @kropot
The question mark is necessary if there's anything after it. In this case the 2nd example has 't=69' so the question mark stays. (t for where in the video to start)

But in general, you can remove the question mark and anything after it and you get the original video without fuss.

@StroomAfwaarts @trinsec @kropot In general, links with parameters work like this:

link/to/file/on/the/internet
?
parameter1=value1
&
parameter2=value2
&
parameter3=value3

So, you delete the parameter=value bit and the separator before it (? or &) if you want to get rid of it.

Youtube links can also look like this:
youtube.com/watch?v=videoid&si=trackingid&t=69

In this case you delete &si=trackingid

@StroomAfwaarts @kropot The question mark separates the URL from the parameters. Ampersand separates the parameters from each other.

In the first URL, the tracking junk was the only parameter, so everything can be removed. In the second, it's leaving behind the time code parameter.

On links to youtube.com (as opposed to youtu.be) the video ID is itself a parameter /watch?v=etc, so you'd always be leaving the question mark.