To clarify:

: This is a core Google search operator. It restricts results to web pages where the specified text string is found directly inside the URL.

: This is a standard directory path and file format natively used by older network surveillance hardware, most notably manufactured by AXIS Communications. The .shtml extension indicates a Server Side Includes HTML file, which dynamically pulls live video feeds onto the page.

This is the precise path structure used by the firmware of several legacy network devices—most notably older IP surveillance cameras manufactured by brands like Axis Communications. The file extension .shtml indicates a Server Side Includes (SSI) HTML document, which dynamically pulls live server data (such as a live video stream framework) into the user's browser.

: Likely a specific date parameter (April 2021 or 24th of a month in 2021) or part of a file naming convention that the user is trying to narrow down, indicating an interest in files from that specific period.