LaunchServicesAllRoleHandlersForContentTypeMBS(ContentType as string, role as Integer) as LaunchServicesStringListMBS

dim l as LaunchServicesStringListMBS
dim s(-1) as string
dim i,c as Integer

const kLSRolesAll=-1

l=LaunchServicesAllRoleHandlersForContentTypeMBS("com.adobe.pdf",kLSRolesAll)
if l<>nil then
  c=l.Count-1
  for i=0 to c
    s.Append l.Item(i)
  next
  
  MsgBox Join(s,", ")
end if

Application content handling capabilities are determined according to the kCFBundleDocumentTypes listed in an application's Info.plist). For any role, specify kLSRolesAll.
Returns nil if no handlers are available.
Requires Mac OS X 10.4.

Constants you can use for the role parameter:

kLSRolesNone	= 1	no claim is made about support for this type/scheme
kLSRolesViewer	= 2	claim to be able to view this type/scheme
kLSRolesEditor	= 4	claim to be able to edit this type/scheme
kLSRolesAll	= -1	claim to do it all

Example output for code above is:
com.adobe.Reader, com.apple.preview, com.adobe.acrobat.reader, com.apple.MDIimporter.PDF