I figured out, by accident, that I can extract .exe executables (what for?).
Though the files make no sense whatsoever, how do I put those extracted files back into an .exe executable?
Many installers use self-extracting archives (SFX) to pack a compressed file archive together with the programming necessary to extract the archive. With SFX, you don't need an external application to extract the files. Historically, this avoided the problem of downloading a program archive and not having an extraction tool.
WinZip/WinRAR/7Zip and similar archiving utilities allow you to create an SFX archive containing any files you like. Some of these tools may allow you to "edit" an existing SFX .EXE, by allowing you to replace a file in the archive with an updated version of the file.
The files you extracted are probably components of a program, and depending on the program might include a separate installer (.msi), a program (.exe), code libraries (.dll), documentation (.txt, .doc, .html, etc), and/or any of a wide variety of other filetypes.
Using 7-Zip to open executable files is generally useful for installers that you don't want to install, either because of one or two files needed, or an application can run portably and install isn't an option with your permissions.
Last time I checked (I could be outdated here) 7-Zip couldn't put the files back in, but if you want to make a self-extractor for pure unzipping files, 7-Zip can do that.
If you want to edit the installer there are separate programs for that.