The URL's for YouTube Clips appear to follow no logic other than they have:
https://youtube.com/clip/Ugkx
+ 32 characters.
For example, for a 15 second clip starting at the beginning of:
https://www.youtube.com/watch?v=NiXD4xVJM5Y&ab_channel=JamieDupuis
The link is:
https://youtube.com/clip/UgkxU2HSeGL_NvmDJ-nQJrlLwllwMDBdGZFs
There is nothing in the URL that would suggest it starts at 0 seconds, last 15 seconds or comes from video ID NiXD4xVJM5Y.
From the HTML I was able to find:
<html>
...
<body>
...
<ytd-app>
...
<div#content.style-scope.ytd-app>
...
<ytd-page-manager#page-manager.style-scope.ytd-app>
...
<ytd-watch-flexy class="style-scope ytd-page-manager hide-skeleton" video-id="NiXD4xVJM5Y"...>
But I cannot find the start point, end point, and/or duration.
Ideally, I would use a Python package to read the HTML, get the start and end point or get the start point and determine the end point by adding the duration.