PROPERTY: VALUE (default OPERATOR is eq)

or

PROPERTY: ["in", VALUE, VALUE(, VALUE ...)] (default OPERATOR is eq)
or
PROPERTY: [OPERATOR, VALUE]

OPERATOR: VALUE (default PROPERTY is content)

or

OPERATOR: ["in", VALUE, VALUE(, VALUE ...)] (default PROPERTY is content)

RELATIONSHIP: CARD_DEFINITION

ARRANGEMENT: (depends on arrangement)

Properties - id, name, type, content, count
Operators - match, gt, lt, eq, ne

Relationships
References: link_to, linked_to_by, include, included_by, refer_to, referred_to_by (refer = link or include)
Plus cards: part, left, right, plus, left_plus, right_plus
Accounts: member_of, member, edited_by, edited
Contextual: _self, _left, _right, _user

Arrangements
limit: number OR (two?) numbers (goes directly into sql)
sort: update, create, name, plusses[?], OR relevance[?]
dir: asc OR desc

view: closed (default), open, titled, content, naked, raw, change, link, name, linkname (see views)

append/prepend

Combining searches: found_by

(What are "or" and "and" and "not"?)