A quick HOW TO :P
if you want to IMPORT one from another app it definitely helps to have the other app available (its kind of required in a lot of cases)
You CAN open its plist if you definitely need to and peek at the plists Exported Type UTI's in Xcodes plist editor
And since you can use find to find text in any of the fields in the UTI you can search for the extension, name, etc
Apple has a list of common ones on their web site
And once you get things set up you can use mdls <filename> to see IF you have things set up right
Or to examine the attributes of the file to see what known UTI it conforms to etc
For instance, on my machine, the IDE project file gives the following and you can see that the "kMDItemContentType" tells you what UTI and "kMDItemContentTypeTree " the content hierarchy it is in
- yes the IDE is still a rbvcp project since it would require a pile of unnecessary svn moves etc to change it for no real benefit -
server:~ npalardy$ mdls IDE.rbvcp
_kMDItemOwnerUserID = 501
kMDItemContentCreationDate = 2017-10-12 01:13:25 +0000
kMDItemContentModificationDate = 2017-10-12 01:13:25 +0000
kMDItemContentType = "com.realsoftware.realstudio.plain-text-project"
kMDItemContentTypeTree = (
kMDItemDateAdded = 2017-10-12 01:13:25 +0000
kMDItemDisplayName = "IDE.rbvcp"
kMDItemFSContentChangeDate = 2017-10-12 01:13:25 +0000
kMDItemFSCreationDate = 2017-10-12 01:13:25 +0000
kMDItemFSCreatorCode = ""
kMDItemFSFinderFlags = 0
kMDItemFSHasCustomIcon = (null)
kMDItemFSInvisible = 0
kMDItemFSIsExtensionHidden = 0
kMDItemFSIsStationery = (null)
kMDItemFSLabel = 0
kMDItemFSName = "IDE.rbvcp"
kMDItemFSNodeCount = (null)
kMDItemFSOwnerGroupID = 20
kMDItemFSOwnerUserID = 501
kMDItemFSSize = 140670
kMDItemFSTypeCode = ""
kMDItemKind = "REAL Studio Project"
kMDItemLogicalSize = 140670
kMDItemPhysicalSize = 143360
mdls is a handy UTI debugging tool along with lsregister