Hello Jakob,
Tools don't have a unique link by default. What is possible, is to add an "id" attribute in the HTML source of an HTML tool:
So double click any HTML tool, click the "html" button to open html source, here you have the option to change the inner html by hand. You can now use standard HTML anchor id's.
For example:
<p> some text that you wrote </p>
becomes:
<p id="myAnchorName1">some text that you wrote</p>
You can then use the # in your exposition link:
https://www.researchcatalogue.net/view/123456/123456#myAnchorName1
The behavior of standard HTML anchors is a little bit different from RC position links, in that linking to an HTML anchor will scroll it in view, but not put it in the left top corner. This can be disorienting for the reader, therefore I personally still use position links instead of anchors, but that is maybe a matter of taste. The advantage of the id-based anchor is that it does move with the tool.
We are working on an update of the RC editor, which is a big update which will also merge the currently separated text-based format with the graphical editor. This will support linking any tool, since that is a requirement for making links compatible in both the original graphical version and the text based "responsive" format. We currently are scheduling this to become available somewhere this year.