> db.ts.aggregate([{$match: {tag: "a"}}, {$project: {f: 1, time: 1, tag: 1}}], {collation: {locale: "en", strength: 1}});
[2] mkbson s13 [_id = s10, f = s11, time = s12, tag = s6] true false
[2] block_to_row blocks[s7, s8, s9] vals[s10, s11, s12]
[2] ts_bucket_to_cellblock s2 paths[s7  =  _id, s8  =  f, s9  =  time] meta =  s6
[1] filter {traverseF(s1, lambda(l1.0) { ((l1.0 ==[s5] s4) ?: false) }, false)}
[1] scan s2 s3 none none none none none none lowPriority [s1 = meta] @"2238077b-8893-4b6c-bbb4-21b5f72c55de" true false

> db.ts.aggregate([{$match: {tag: {$in: ["a", "c"]}}}, {$project: {f: 1, time: 1, tt: {$concat: ["$tag", "-", "abc"]}, ss: {$concat: ["$tag", "XYZ"]}}}], {collation: {locale: "en", strength: 1}});
[3] mkbson s15 [_id = s12, f = s13, time = s14, ss = s7, tt = s8] true false
[3] block_to_row blocks[s9, s10, s11] vals[s12, s13, s14]
[3] ts_bucket_to_cellblock s6 paths[s9  =  _id, s10  =  f, s11  =  time]
[2] project [s7 = getField(s6, "ss"), s8 = getField(s6, "tt")]
[2] project [s6 = makeBsonObj(MakeObjSpec(drop, [], ["tt", "ss"]), s2,
    if (typeMatch(s1, 1088ll) ?: true)
    then null
    else
        if isString(s1)
        then concat(s1, "-abc")
        else fail(7158201, "$concat supports only strings")
,
    if (typeMatch(s1, 1088ll) ?: true)
    then null
    else
        if isString(s1)
        then concat(s1, "XYZ")
        else fail(7158201, "$concat supports only strings")
)]
[1] filter {traverseF(s1, lambda(l1.0) { isMember(l1.0, s4) }, false)}
[1] scan s2 s3 none none none none none none lowPriority [s1 = meta] @"2238077b-8893-4b6c-bbb4-21b5f72c55de" true false