# fish --version
fish, version 3.6.1
# zfs load-key r[TAB]: _: cannot overwrite read-only variable
/usr/share/fish/functions/__fish_is_zfs_feature_enabled.fish (line 12): 
    echo $feature_name | read -l _ _ state _
    ^
in function '__fish_is_zfs_feature_enabled' with arguments 'feature@bookmarks'
	called on line 344 of file /usr/share/fish/completions/zfs.fish
from sourcing file /usr/share/fish/completions/zfs.fish

(Type 'help read' for related documentation)
read: _: cannot overwrite read-only variable
/usr/share/fish/functions/__fish_is_zfs_feature_enabled.fish (line 12): 
    echo $feature_name | read -l _ _ state _
    ^
in function '__fish_is_zfs_feature_enabled' with arguments 'feature@bookmarks'
	called on line 508 of file /usr/share/fish/completions/zfs.fish
from sourcing file /usr/share/fish/completions/zfs.fish

(Type 'help read' for related documentation)
read: _: cannot overwrite read-only variable
/usr/share/fish/functions/__fish_is_zfs_feature_enabled.fish (line 12): 
    echo $feature_name | read -l _ _ state _
    ^
in function '__fish_is_zfs_feature_enabled' with arguments 'feature@extensible_dataset'
	called on line 548 of file /usr/share/fish/completions/zfs.fish
from sourcing file /usr/share/fish/completions/zfs.fish

(Type 'help read' for related documentation)