/test.mp3:
$ fq -i -d mp3 . /test.mp3
mp3> .headers[0].flags.unsynchronisation | ., tovalue, type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|               00                              |     .          |.headers[0].flags.unsynchronisation: false
false
"boolean"
mp3> .headers[0].flags.unsynchronisation[0] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation[-1000] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation[1000] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation[1:3] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation[0:-1] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation[-1000:2000] | ., type, length?
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation["test"] | ., type, length?
error: expected an object but got: boolean
mp3> [.headers[0].flags.unsynchronisation[]] | type, length?
error: cannot iterate over: boolean
mp3> .headers[0].flags.unsynchronisation | keys
error: keys cannot be applied to: boolean
mp3> .headers[0].flags.unsynchronisation | has("a")
error: has cannot be applied to: boolean
mp3> .headers[0].flags.unsynchronisation | has(0)
error: has cannot be applied to: boolean
mp3> .headers[0].flags.unsynchronisation | type
"boolean"
mp3> .headers[0].flags.unsynchronisation | tonumber
error: tonumber cannot be applied to: boolean
mp3> .headers[0].flags.unsynchronisation | tostring
"false"
mp3> .headers[0].flags.unsynchronisation + ""
error: cannot add: boolean (false) and string ("")
mp3> .headers[0].flags.unsynchronisation + 1
error: cannot add: boolean (false) and number (1)
mp3> .headers[0].flags.unsynchronisation._start | ., type, length?
40
"number"
40
mp3> .headers[0].flags.unsynchronisation._stop | ., type, length?
41
"number"
41
mp3> .headers[0].flags.unsynchronisation._len | ., type, length?
1
"number"
1
mp3> .headers[0].flags.unsynchronisation._name | ., type, length?
"unsynchronisation"
"string"
17
mp3> .headers[0].flags.unsynchronisation._symbol | ., type, length?
""
"string"
0
mp3> .headers[0].flags.unsynchronisation._description | ., type, length?
""
"string"
0
mp3> .headers[0].flags.unsynchronisation._path | ., type, length?
[
  "headers",
  0,
  "flags",
  "unsynchronisation"
]
"array"
4
mp3> .headers[0].flags.unsynchronisation._bits | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|                |
0x0|00                                             |.               |
<1 bits>
"buffer"
1
mp3> 
mp3> .headers[0].flags.unsynchronisation._bytes | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|                |
0x0|00                                             |.               |
<0 bytes>
"buffer"
0
mp3> 
mp3> .headers[0].flags.unsynchronisation._error | ., type, length?
null
"null"
0
mp3> .headers[0].flags.unsynchronisation._unknown | ., type, length?
false
"boolean"
mp3> .headers[0].flags.unsynchronisation.a = 1
error: expected an object but got: boolean
mp3> .headers[0].flags.unsynchronisation[0] = 1
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation.a |= empty
error: expected an object but got: boolean
mp3> .headers[0].flags.unsynchronisation[0] |= empty
error: expected an array but got: boolean
mp3> .headers[0].flags.unsynchronisation | setpath(["a"]; 1)
error: expected an object with key "a" but got: boolean
mp3> .headers[0].flags.unsynchronisation | setpath([0]; 1)
error: expected an array with index 0 but got: boolean
mp3> .headers[0].flags.unsynchronisation | delpaths([["a"]])
error: expected an object with key "a" but got: boolean
mp3> .headers[0].flags.unsynchronisation | delpaths([[0]])
error: expected an array with index 0 but got: boolean
mp3> ^D