Currently, we can create a link but not modify or remove it.
Would be nice if it was possible without going to the code.
A fix is available in the development tree.
Links can now be modified.
Another extension will be provided to remove Links.
Another user observed that Inkscape already allows to create, edit and remove links.
Right-click on an element and use the appropriate item in the pop-up menu: "Create Link", "Link Properties", "Remove Link".