I need to add some variable content to the issue and the archive page, but I habe trouble to find the right hook. For example ‘Templates::Issue::Main’ doesn’t seem to work. Do these hooks even exist? And if not, can I create my own hook?
There’s a general TemplateManager::display hook that is broadly useful for this sort of thing. Have a look at how it’s implemented in the orcidProfile/OrcidProfilePlugin.inc.php, for instance. There’s some code in the registered function that determines what template is being loaded and calls the appropriate functions.