Can you post a link if the page doesn't require authentication?

Maybe you need in install the Gecko Media player plugin and Gnome MPlayer.

• https://support.mozilla.com/kb/Using+the+Windows+Media+Player+plugin+with+Firefox
• https://support.mozilla.com/kb/Popular+plugins

http://patimg1.uspto.gov/.piw?Docid=06768109&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D6768109.PN.%2526OS%3DPN%2F6768109%2526RS%3DPN%2F6768109&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

You need a TIFF image viewer. Try this one.
http://projects.gnome.org/evince/?guid=on

Unfortunately, I already have evince installed, but it doesn't work as a plugin. Nor does this answer my original question.

Issues related to plugins

• http://kb.mozillazine.org/Issues_related_to_plugins

Check and tell if its working.

There's nothing there that answers my question.

By the way, the patent office makes invalid TIFF files. I downloaded them and converted them to GIFs with ImageMagick. But, that's a secondary issue: what I want to know is how one can figure out what plugin the browser is trying to find. There's no way as far as I can tell without looking at the source text to get even a hint at what it's looking for. And, if the source text is written obscurely, even that method will fail. Where does the browser display information about the plugin it's looking for?

Normally when you go to a website and it tells you that you need to Install a Supporting Plugin, it also provides the information about the Missing Plugin. Sorry i can't help much cause i don't use Linux therefore i got no idea how to point you to the right direction. You can try asking the Website Developers about this issue..

Well, on Windows, it's even worse. It tells you you need to install Quicktime, so you install it and it still doesn't work. It never mentions the MIME type it was trying to process on either Windows or Linux. That's pretty lame behavior in my opinion.

If by Website Developers you're referring to the Patent Office, they are government employees and, therefore, totally brainless. They have a deal with a company which produces a TIFF viewer for their nonstandard TIFF format. That's how corrupt the government is these days---taking bribes from private companies using non-standard software on our publically-financed websites.

Found this link, maybe it'll be helpful to you:

• http://plugindoc.mozdev.org/

Thanks, but I've been over it and there's no way to find out what MIMEtype the browser is looking for. Somehow over the years that functionality got lost in the mix. So, if the browser can't match the MIME type, I guess the only reliable way to do it is to run it under a debugger and trap it. It would have been so easy to simply put it in the message either before it tries to match the plugin or after it fails, but no, we wouldn't want to actually be helpful to the end user who's left completely in the dark.

By the way, Chromium is even worse. It simply puts a statement, "MIssing Plug-In" and doesn't even voluteer to try to find one that matches!

Correction: Chromium spits the following to stderr: "[12636:12668:324242133947:ERROR:nss_ocsp.cc(581)] No URLRequestContext for OCSP handler."

Which isn't really helpful.

Try this bookmarklet.

javascript:(function(){window.open(document.embeds[0].src)})();

• http://en.wikipedia.org/wiki/Bookmarklet

Thanks. In the meantime, I found a way to do it. Do ^I and examine the media tab. The offending plugin MIME type is displayed as "TIFF image".