Yeah, you’re right on that you needed to check for Flash if your site used it. But at the risk of sounding overly pedantic: Flash wasn’t a browser extension either; it was a plugin, which though named similarly were completely different implementation-wise. Browser plugins are not really supported anymore in 2026, due to them having essentially unrestricted access to the host machine.

I have been doing web development pretty much since the web was created.

“Sniffing your browser extensions is normal to be able to render the page correctly” is not and was never a sensible argument. 20 years ago, neither Chrome nor the iPhone existed yet. Most people browsed the web on computers, and “works best in Internet Explorer” was widespread. Web developers were lazy and many of them literally only tested their sites in IE on Windows. Browser extensions themselves were much more of a niche thing since IE didn’t support them.

Thanks, I worked in adtech for a number of years so I’m aware of this use case. I could tell some stories that would likely surprise you at how sophisticated that industry has been for a long time, even as long as 10-15 years ago.

But the parent post specifically said this was “sensible” and maybe “normal” to do this to decide how to render a page. My question was specifically how that claim makes sense at all.

In what fucking world is it “normal” or “sensible” to scan your browser extensions to decide how to render a page? Please explain.

I’ve been doing web development for 30 years (since the time when “SSR” was just called “building a web app”) and I have not once ever had the desire or need to do this.

Arrest and prosecute this piece of shit senator.

Here’s an archive link, in case anyone, like me, refuses to read anything on Substack due to their affinity for Nazis:

https://archive.ph/Qh4gw