filetype detection mechanism prevents ELF files with no extension from being installed

[kStor2poche]

When trying to install TowerFall Ascension in the itch.io linux app, it fails with the following error:

13:38	butler	Queuing install for TowerFall Ascension - https://maddymakesgamesinc.itch.io/towerfall
13:38	butler	Generated fresh cave 4d515789-e941-488f-88ff-08f91866d387
13:38	butler	Upload specified:
13:38	butler	  ☁ tfitch-07212016-bin :: 248.81 MiB :: #243755
13:38	butler	    Executable :: Linux all
13:38	butler	Upload is not wharf-enabled
13:38	butler	→ Performing install for TowerFall Ascension - https://maddymakesgamesinc.itch.io/towerfall
13:38	butler	    to (/home/user/.config/itch/apps/towerfall)
13:38	butler	    via (/home/user/.config/itch/apps/downloads/urgently-just-shepherd)
13:38	butler	No receipt found.
13:38	butler	→ Starting fresh download session (ca425ce4-640c-438c-8ce5-42426bb5f1ef)
13:38	butler	← No previous install info (no recorded upload or build)
13:38	butler	→ To be installed:
13:38	butler	  ☁ tfitch-07212016-bin :: 248.81 MiB :: #243755
13:38	butler	    Executable :: Linux all
13:38	butler	(opening file took 390.537444ms)
13:38	butler	Determining source information...
13:38	butler	↝ For source (tfitch-07212016-bin)
13:38	butler	  No mapping for file extension ()
13:38	butler	Estimated disk usage (accuracy: guess)
13:38	butler	  ✓ 572.26 MiB needed free space
13:38	butler	  ✓ 323.45 MiB final disk usage
13:38	butler	Will use installer unknown
13:38	butler	No manager for installer unknown
github.com/itchio/butler/cmd/operate.doInstallPerformInner.func1
	/__w/butler/butler/cmd/operate/install_perform.go:266
github.com/itchio/butler/cmd/operate.InstallPrepare
	/__w/butler/butler/cmd/operate/install_prepare.go:264
github.com/itchio/butler/cmd/operate.doInstallPerformInner
	/__w/butler/butler/cmd/operate/install_perform.go:202
github.com/itchio/butler/cmd/operate.doInstallPerform
	/__w/butler/butler/cmd/operate/install_perform.go:137
github.com/itchio/butler/cmd/operate.InstallPerform
	/__w/butler/butler/cmd/operate/install_perform.go:40
github.com/itchio/butler/endpoints/downloads.performOne.func8
	/__w/butler/butler/endpoints/downloads/downloads_drive.go:328
github.com/itchio/butler/endpoints/downloads.performOne
	/__w/butler/butler/endpoints/downloads/downloads_drive.go:333
github.com/itchio/butler/endpoints/downloads.DownloadsDrive
	/__w/butler/butler/endpoints/downloads/downloads_drive.go:73
github.com/itchio/butler/endpoints/downloads.Register.(*DownloadsDriveType).Register.func4
	/__w/butler/butler/butlerd/messages/messages.go:2782
github.com/itchio/butler/butlerd.(*Router).HandleRequest.func2
	/__w/butler/butler/butlerd/router.go:304
github.com/itchio/butler/butlerd.(*Router).HandleRequest
	/__w/butler/butler/butlerd/router.go:313
github.com/itchio/butler/butlerd.(*gatedHandler).HandleRequest
	/__w/butler/butler/butlerd/butlerd.go:179
github.com/itchio/butler/butlerd/jsonrpc2.(*connImpl).handleIncomingMessage.func1
	/__w/butler/butler/butlerd/jsonrpc2/jsonrpc2.go:250
runtime.goexit
	/__t/go/1.24.0/x64/src/runtime/asm_amd64.s:1700

Upon a quick research online, it seems that the problem may come from this project.