Is it possible to change 1 parameter in all jenkins projects?

Question

Jenkins

How is it possible to change/add the value of the Item parameter in jenkins?

I will assume that with the help of Jenkins CLI , but I could not find an example of this on the Internet.
As far as I understand, each Jenkins project should have a json or yaml description. In this case, it would be possible to write a script that added / replaced the parameter, but I couldn’t find such a description in my place ..
Or maybe there is REST or WSDL to which you can suck and correct the values ​​..

For example, I need to add to the settings of each project: in the "Projects" block, the "Behaviours" subblock and there the "Discover merge requests from origin" parameter

If you have any thoughts on this, please share.
It seems that such an ordinary thing, there should be just millions of manuals for such

Answer 1

I haven't researched seriously, but IMHO - no, it's impossible. Because projects are different.
If you are interested in a specific parameter for specific projects, look at their XML and come up with some kind of script.

Answer 2

Use Vault for example, you can load the key value there and build json with parameters