Hello,
I’m looking for a possibility to export a list with the geographic coordinates of administrative boundary’s, I found on OSM.
Is there a easy way to get that? Otherwise I need to open every line and the related knots of this lines, in order to get this coordinates, which is a lot of work to do for about 100 boundary’s. 
What do you need it for? It could make the response easier, both because the usage and the scale of objects can be important.
You can use Overpass Turbo service for example:
http://overpass-turbo.eu/s/tun
There are multiple export options, but the easiest is to just change the tab from “map” to “data” and you have lat/lon for all the nodes in pretty simple boundary of Wyoming, USA.
For performance reasons the data tab always shows a small subset of the query result only. It is therefore not recommended for copy&paste operations, as you would miss out on some of the data. Better use the Export button options when exporting data.
For admin boundaries you should as well take a look at user wambacher‘s boundary map and download boundaries there.