On Windows, the Wireshark File -> Open dialog has a "Files of type:" widget that lets you choose "All Files" or files of various types.
In current Wireshark releases, some of those options aren't really useful, as not all file types have standard extensions, and so their options just select use *.* and show all files. Some other file formats are text file formats without standard extensions, and show *.txt and *.txt.gz files, so their options show text files that aren't capture files.
In addition, the extension .cap is used for several different file formats, so the options for NetXRay/Windows Sniffer, Microsoft Network Monitor, and Shomiti/Finisar Surveyor files all show *.cap and *.cap.gz files and thus show files of all those types.
The GTK+ version in the development release adds "All Capture Files", which shows files with all extensions Wireshark knows about (which means it won't see the file types that don't have standard extensions), doesn't have options for file types without standard extensions (as they're either no different from "All Files" or they're just "show all .txt files"), and lumps all the .cap files into one item.
Are any of those options useful (other than, obviously, "All Files")?
Would options that select files based on the files' *contents*, rather than their *file extensions* - which would correctly identify the particular file type of .cap files, distinguish between various text file formats that are capture files and text file formats that aren't capture files, and identify files that don't have extensions - be useful?
I don't know whether those options could be implemented in the Open dialog on all platforms, and, if they *are* implemented, selecting one of the options would require that all files in the folder be opened, which could take a significant amount of time, especially in a directory with lots of files or a directory mounted from a file server, so it wouldn't be "free".
