This is about an early browser called OWL, not the Web Ontology Language (OWL)[0].<p>[0] <a href="https://www.w3.org/OWL/" rel="nofollow">https://www.w3.org/OWL/</a>
> Not all of these have direct analogues with HTML5 (in fact, action buttons could even run shell scripts!) and some of their core conceits are rather different. Indeed, its most pervasive and interesting navigational mechanism is the concept of replacement: embedding the content referred to by a link ("replace button") directly where it was referenced.<p>Looking at their examples, this seems to be directly analogous to collapsible disclosure elements in HTML5 using <details>: <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/details" rel="nofollow">https://developer.mozilla.org/en-US/docs/Web/HTML/Element/de...</a><p>(The later part about linking to different states of expansion is not, although I suppose you could record the open/close state of the hierarchy & stash in a cookie/local-storage and replay it with JS.)