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Description of problem:
RISC OS archive (spark format) collides with Matroska, and is given preference. It also seems like it would collide with terminfo, but I haven't checked that.

# Acorn archive formats (Disaster prone simpleton, m91dps@ecs.ox.ac.uk)
# I can't create either SPARK or ArcFS archives so I have not tested this stuff
# [GRR:  the original entries collide with ARC, above; replaced with combined
#  version (not tested)]
#0      byte            0x1a            RISC OS archive
#>1     string          archive         (ArcFS format)
#0      string          \032archive     RISC OS archive (ArcFS format)
0       string          \032            RISC OS archive (spark format)
0       string          Archive\000     RISC OS archive (ArcFS format)


#------------------------------------------------------------------------------
# terminfo:  file(1) magic for terminfo
#
# XXX - byte order for screen images?
#
0       string          \032\001        Compiled terminfo entry
0       short           0433            Curses screen image
0       short           0434            Curses screen image



#------------------------------------------------------------------------------
# matroska:  file(1) magic for Matroska files
#
# See http://www.matroska.org/
#

# EBML id:
0               belong          0x1a45dfa3
# DocType id:
>5              beshort         0x4282
# DocType contents:
>>8             string          matroska        Matroska data


Version-Release number of selected component (if applicable):
file-4.13-1

How reproducible:
Always

Steps to Reproduce:
1. Execute file on a Matroska file

Actual Results:  It says RISC OS archive (spark format)

Expected Results:  It should say Matroska data

Additional info: