Small edits

apiary.apib

@@ -1741,7 +1741,7 @@ Import a tar file into IPFS.
 
     The response is the same if the argument is invalid. For example:
 
-        curl -i -F "data=@test" -X POST http://localhost:5001/api/v0/tar/add"
+        curl -i -F "data=@test" -X POST "http://localhost:5001/api/v0/tar/add"
 
     Where 'test' is not a tarball.
 
@@ -1939,6 +1939,8 @@ Export a tar file from IPFS
 
 + Request With Argument
 
+    This call depends on the given hash being a tar file.
+
     #### curl
 
         curl -i "http://localhost:5001/api/v0/tar/cat?arg=QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ"
@@ -1951,6 +1953,8 @@ Export a tar file from IPFS
 
 + Response 200
 
+    The Content-Type of the response should be `application/x-tar`.
+
     + Headers
 
         ```