+ Here is a table that summarizes the functionality of each of these
+ policies:
+
+ +------------------------+-------+------+---------+------+
+ | | false | auto | nostash | true |
+ +========================+=======+======+=========+======+
+ | Index cleartext using | | X | X | X |
+ | stashed session keys | | | | |
+ +------------------------+-------+------+---------+------+
+ | Index cleartext | | | X | X |
+ | using secret keys | | | | |
+ +------------------------+-------+------+---------+------+
+ | Stash session keys | | | | X |
+ +------------------------+-------+------+---------+------+
+ | Delete stashed session | X | | | |
+ | keys on reindex | | | | |
+ +------------------------+-------+------+---------+------+
+
+ Stashed session keys are kept in the database as properties
+ associated with the message. See ``session-key`` in
+ :any:`notmuch-properties(7)` for more details about how they can be
+ useful.
+
+ Be aware that the notmuch index is likely sufficient (and a
+ stashed session key is certainly sufficient) to reconstruct the
+ cleartext of the message itself, so please ensure that the notmuch
+ message index is adequately protected. DO NOT USE
+ ``index.decrypt=true`` or ``index.decrypt=nostash`` without
+ considering the security of your index.
+
+ Default: ``auto``.
+
+**index.header.<prefix>**
+ Define the query prefix <prefix>, based on a mail header. For
+ example ``index.header.List=List-Id`` will add a probabilistic
+ prefix ``List:`` that searches the ``List-Id`` field. User
+ defined prefixes must not start with 'a'...'z'; in particular
+ adding a prefix with same name as a predefined prefix is not
+ supported. See :any:`notmuch-search-terms(7)` for a list of existing
+ prefixes, and an explanation of probabilistic prefixes.
+
+**built_with.<name>**
+ Compile time feature <name>. Current possibilities include
+ "retry_lock" (configure option, included by default).
+ (since notmuch 0.30, "compact" and "field_processor" are
+ always included.)
+
+**query.<name>**
+ Expansion for named query called <name>. See
+ :any:`notmuch-search-terms(7)` for more information about named
+ queries.
+
+FILES
+=====
+
+CONFIGURATION
+-------------
+
+Notmuch configuration file search order:
+
+1. File specified by :option:`notmuch --config` global option; see
+ :any:`notmuch(1)`.
+
+2. File specified by :envvar:`NOTMUCH_CONFIG` environment variable.
+
+3. ``$XDG_CONFIG_HOME/notmuch/<profile>/config`` where ``<profile>``
+ is defined by :envvar:`NOTMUCH_PROFILE` environment variable if
+ set, ``$XDG_CONFIG_HOME/notmuch/default/config`` otherwise.
+
+4. ``$HOME/.notmuch-config.<profile>`` where ``<profile>`` is defined
+ by :envvar:`NOTMUCH_PROFILE` environment variable if set,
+ ``$HOME/.notmuch-config`` otherwise.
+
+.. _database:
+
+DATABASE LOCATION
+-----------------
+
+Notmuch database search order:
+
+1. Directory specified by :envvar:`NOTMUCH_DATABASE` environment variable.
+
+2. Directory specified by config key ``database.path``.
+
+3. ``$XDG_DATA_HOME/notmuch/<profile>`` where ``<profile>``
+ is defined by :envvar:`NOTMUCH_PROFILE` environment variable if
+ set, ``$XDG_DATA_HOME/notmuch/default`` otherwise.
+
+4. Directory specified by :envvar:`MAILDIR` environment variable.
+
+5. ``$HOME/mail``
+
+HOOKS
+-----
+
+Notmuch hook directory search order:
+
+1. Directory specified by ``database.hook_dir`` configuration option.