I noticed that some apps have their own protocols like zotero://, goldendict:// etc. And some functions can be invoked by such url like that zotero://open-pdf/library/items/AABBCCDD?annotation=[annotation-key] can open a pdf in zotero. It will open a pdf when I type the url in a browser.
I know protocols like http have some RFCs and they can be recognized by all browsers. So I am wondering how do these app-specific protocols work? What are the principles and theories under this.
Thanks in advance!