/etc/bash_completion.d/findutils is in bash-completion 1:1.3-1ubuntu8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | # bash completion for GNU find. This makes heavy use of ksh style extended
# globs and contains Linux specific code for completing the parameter
# to the -fstype option.
have find &&
_find()
{
    local cur prev i exprfound onlyonce
    COMPREPLY=()
    _get_comp_words_by_ref cur prev
    case $prev in
        -maxdepth|-mindepth)
            COMPREPLY=( $( compgen -W '0 1 2 3 4 5 6 7 8 9' -- "$cur" ) )
            return 0
            ;;
        -newer|-anewer|-cnewer|-fls|-fprint|-fprint0|-fprintf|-name|-iname|\
        -lname|-ilname|-wholename|-iwholename|-samefile)
            _filedir
            return 0
            ;;
        -fstype)
            _fstypes
            if [[ "$( uname -s )" == *BSD ]] ; then
                COMPREPLY=( "${COMPREPLY[@]}" \
                    $( compgen -W 'local rdonly' -- "$cur" ) )
            fi
            return 0
            ;;
        -gid)
            _gids
            return 0
            ;;
        -group)
            COMPREPLY=( $( compgen -g -- "$cur" 2>/dev/null) )
            return 0
            ;;
        -xtype|-type)
            COMPREPLY=( $( compgen -W 'b c d p f l s' -- "$cur" ) )
            return 0
            ;;
        -uid)
            _uids
            return 0
            ;;
        -user)
            COMPREPLY=( $( compgen -u -- "$cur" ) )
            return 0
            ;;
        -exec|-execdir|-ok|-okdir)
            COMP_WORDS=(COMP_WORDS[0] "$cur")
            COMP_CWORD=1
            _command
            return 0
            ;;
        -[acm]min|-[acm]time|-iname|-lname|-wholename|-iwholename|-lwholename|\
        -ilwholename|-inum|-path|-ipath|-regex|-iregex|-links|-perm|-size|\
        -used|-printf|-context)
            # do nothing, just wait for a parameter to be given
            return 0
            ;;
        -regextype)
            COMPREPLY=( $( compgen -W 'emacs posix-awk posix-basic \
                posix-egrep posix-extended' -- "$cur" ) )
            return 0
            ;;
    esac
    _expand || return 0
    # set exprfound to 1 if there is already an expression present
    for i in ${COMP_WORDS[@]}; do
        [[ "$i" = [-\(\),\!]* ]] && exprfound=1 && break
    done
    # handle case where first parameter is not a dash option
    if [[ "$exprfound" != 1 && "$cur" != [-\(\),\!]* ]]; then
        _filedir -d
        return 0
    fi
    # complete using basic options
    COMPREPLY=( $( compgen -W '-daystart -depth -follow -help \
        -ignore_readdir_race -maxdepth -mindepth -mindepth -mount \
        -noignore_readdir_race -noleaf -regextype -version -warn -nowarn \
        -xdev \
        -amin -anewer -atime -cmin -cnewer -ctime -empty -executable -false \
        -fstype -gid -group -ilname -iname -inum -ipath -iregex -iwholename \
        -links -lname -mmin -mtime -name -newer -nogroup -nouser -path -perm \
        -readable -regex -samefile -size -true -type -uid -used -user \
        -wholename -writable -xtype -context \
        -delete -exec -execdir -fls -fprint -fprint0 -fprintf -ls -ok -okdir \
        -print -print0 -printf -prune -quit' -- "$cur" ) )
    # this removes any options from the list of completions that have
    # already been specified somewhere on the command line, as long as
    # these options can only be used once (in a word, "options", in
    # opposition to "tests" and "actions", as in the find(1) manpage).
    onlyonce=' -daystart -depth -follow -help -ignore_readdir_race -maxdepth \
       -mindepth -mount -noignore_readdir_race -noleaf -nowarn -regextype \
       -version -warn -xdev '
    COMPREPLY=( $( \
           (while read -d ' ' i; do
            [[ -z "$i" || "${onlyonce/ ${i%% *} / }" == "$onlyonce" ]] &&
            continue
            # flatten array with spaces on either side,
            # otherwise we cannot grep on word boundaries of
            # first and last word
            COMPREPLY=" ${COMPREPLY[@]} "
            # remove word from list of completions
            COMPREPLY=( ${COMPREPLY/ ${i%% *} / } )
            done
            printf '%s ' "${COMPREPLY[@]}") <<<"${COMP_WORDS[@]}"
          ) )
    _filedir
    return 0
} &&
complete -F _find find
# Local variables:
# mode: shell-script
# sh-basic-offset: 4
# sh-indent-comment: t
# indent-tabs-mode: nil
# End:
# ex: ts=4 sw=4 et filetype=sh
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