Search notes:

Firefox profile folder

The profile folder is the location where personal Firefox stuff is stored:

Location of profile folder

The location of the profile folder can be found by entering about:support into the address bar. In the page that opens, it can be searched for Profile Folder (Ctrl-F) next to which the location is revealed.
By default, the profile folder is found in Windows under %APPDATA%\Mozilla\Firefox\Profiles and in Linux under ~/.mozilla/firefox.

Portable apps

Apparently, portable apps starts firefox with the -P option to specify the profile …\PortableApps\FirefoxPortable\Data\profile.
The portable apps profile is claimed to have disk cache turned off.

Content of profile folder

bookmarkbackups This folder stores bookmark backup files. Compare with places.sqlite.
browser-extension-data
crashes
datareporting
extensions Stores the files necessary for extensions.
features
gmp
gmp-gmpopenh264
gmp-widevinecdm
minidumps
saved-telemetry-pings
sessionstore-backups
storage
addons.json
addonStartup.json.lz4
AlternateServices.txt
blocklist.xml
broadcast-listeners.json
cert_override.txt
cert8.db A Berkeley DB file.
cert9.db An SQLite file that stores security certificate settings and SSL certificates imported into Firefox.
compatibility.ini
containers.json
content-prefs.sqlite Compare with permissions.sqlite.
cookies.sqlite stores cookies.
extensions.json
favicons.sqlite The favicons for the stored bookmarks.
formhistory.sqlite stores the autocomplete history: it remembers what was searched in the search bar and what was entered into website forms.
handlers.json what to do for various file types.
key3.db A Berkeley DB file.
key4.db An SQLite file that stores passwords. See also the logins.json file.
logins.json Stores (encrypted) passwords. compare with the key4.db.
notificationstore.json
mimeTypes.rdf On Linux only?
parent.lock
permissions.sqlite An SQLite database that stores permissions given to individual web sites (for example allowing pop-ups or zoom levels). Compare with content-prefs.sqlite.
persdict.dat (?) stores custom words added to Firefox's directory.
pkcs11.txt stores security module configuration.
places.sqlite An SQLite database with the history of visited sites.
prefs.js stores customized user preference settings, such as changes made in options dialogs.
revocations.txt
search.json.mozlz4 stores user-installed search engines.
SecurityPreloadState.txt
serviceworker.txt
sessionCheckpoints.json
shield-preference-experiments.json
shield-recipe-client.json
SiteSecurityServiceState.txt stores HSTS information («supercookies»)
storage.sqlite
Telemetry.FailedProfileLocks.txt
times.json
TRRBlacklist.txt
user.js An optional file to overwrite settings stored in prefs.js.
webappsstore.sqlite DOM storage. Compare with chromeappstore.sql (which apparently is for about:* pages.
xulstore.json toolbar and window size/positions

SQLite databases

content-prefs.sqlite

CREATE TABLE groups (
   id                  INTEGER PRIMARY KEY,
   name                TEXT NOT NULL
)

CREATE INDEX groups_idx ON groups(name)

CREATE TABLE settings (
    id                 INTEGER PRIMARY KEY,
    name               TEXT NOT NULL
)

CREATE INDEX settings_idx ON settings(name)

CREATE TABLE prefs (
   id                  INTEGER PRIMARY KEY,
   groupID             INTEGER          REFERENCES groups(id),
   settingID           INTEGER NOT NULL REFERENCES settings(id),
   value               BLOB,
   timestamp           INTEGER NOT NULL DEFAULT 0
)

CREATE INDEX prefs_idx ON prefs(timestamp, groupID, settingID)

cookies.sqlite

CREATE TABLE moz_cookies (
   id                  INTEGER PRIMARY KEY,
   originAttributes    TEXT NOT NULL DEFAULT '',
   name                TEXT,
   value               TEXT,
   host                TEXT,
   path                TEXT,
   expiry              INTEGER,
   lastAccessed        INTEGER,
   creationTime        INTEGER,
   isSecure            INTEGER,
   isHttpOnly          INTEGER,
   inBrowserElement    INTEGER DEFAULT 0,
   sameSite            INTEGER DEFAULT 0,
   rawSameSite         INTEGER DEFAULT 0,
   schemeMap           INTEGER DEFAULT 0,
   CONSTRAINT          moz_uniqueid UNIQUE (name, host, path, originAttributes)
)

favicons.sqlite

CREATE TABLE moz_icons (
   id                  INTEGER PRIMARY KEY,
   icon_url            TEXT    NOT NULL,
   fixed_icon_url_hash INTEGER NOT NULL,
   width               INTEGER NOT NULL DEFAULT 0,
   root                INTEGER NOT NULL DEFAULT 0,
   color               INTEGER,
   expire_ms           INTEGER NOT NULL DEFAULT 0,
   data BLOB
)

CREATE INDEX moz_icons_iconurlhashindex ON moz_icons (fixed_icon_url_hash)

CREATE TABLE moz_pages_w_icons (
   id                  INTEGER PRIMARY KEY,
   page_url            TEXT NOT NULL,
   page_url_hash       INTEGER NOT NULL
)

CREATE INDEX moz_pages_w_icons_urlhashindex ON moz_pages_w_icons (page_url_hash)

CREATE TABLE moz_icons_to_pages (
   page_id             INTEGER NOT NULL,
   icon_id             INTEGER NOT NULL,
   PRIMARY KEY (page_id, icon_id),
   FOREIGN KEY (page_id) REFERENCES moz_pages_w_icons ON DELETE CASCADE,
   FOREIGN KEY (icon_id) REFERENCES moz_icons         ON DELETE CASCADE
) WITHOUT ROWID

formhistory.sqlite

CREATE TABLE moz_formhistory (
   id                  INTEGER PRIMARY KEY,
   fieldname           TEXT NOT NULL,
   value               TEXT NOT NULL,
   timesUsed           INTEGER,
   firstUsed           INTEGER,
   lastUsed            INTEGER,
   guid                TEXT
)

CREATE INDEX moz_formhistory_index          ON moz_formhistory(fieldname)
CREATE INDEX moz_formhistory_lastused_index ON moz_formhistory(lastUsed)
CREATE INDEX moz_formhistory_guid_index     ON moz_formhistory(guid)

CREATE TABLE moz_deleted_formhistory (
   id                  INTEGER PRIMARY KEY,
   timeDeleted         INTEGER,
   guid                TEXT
)

permissions.sqlite

CREATE TABLE moz_perms (
   id                  INTEGER PRIMARY KEY,
   origin              TEXT,
   type                TEXT,
   permission          INTEGER,
   expireType          INTEGER,
   expireTime          INTEGER,
   modificationTime    INTEGER
)

CREATE TABLE moz_hosts (
   id                  INTEGER PRIMARY KEY,
   host                TEXT,
   type                TEXT,
   permission          INTEGER,
   expireType          INTEGER,
   expireTime          INTEGER,
   modificationTime    INTEGER,
   isInBrowserElement  INTEGER
)

places.sqlite

CREATE TABLE moz_origins (
   id                  INTEGER PRIMARY KEY,
   prefix              TEXT NOT NULL,
   host                TEXT NOT NULL,
   frecency            INTEGER NOT NULL,
   UNIQUE (prefix, host)
)

CREATE TABLE moz_places (
   id                  INTEGER PRIMARY KEY,
   url                 LONGVARCHAR,
   title               LONGVARCHAR,
   rev_host            LONGVARCHAR,
   visit_count         INTEGER DEFAULT  0,
   hidden              INTEGER DEFAULT  0 NOT NULL,
   typed               INTEGER DEFAULT  0 NOT NULL,
   frecency            INTEGER DEFAULT -1 NOT NULL,
   last_visit_date     INTEGER,
   guid                TEXT,
   foreign_count       INTEGER DEFAULT  0 NOT NULL,
   url_hash            INTEGER DEFAULT  0 NOT NULL,
   description         TEXT,
   preview_image_url   TEXT,
   origin_id           INTEGER REFERENCES moz_origins(id)
)

CREATE        INDEX moz_places_url_hashindex      ON moz_places (url_hash)
CREATE        INDEX moz_places_hostindex          ON moz_places (rev_host)
CREATE        INDEX moz_places_visitcount         ON moz_places (visit_count)
CREATE        INDEX moz_places_frecencyindex      ON moz_places (frecency)
CREATE        INDEX moz_places_lastvisitdateindex ON moz_places (last_visit_date)
CREATE UNIQUE INDEX moz_places_guid_uniqueindex   ON moz_places (guid)
CREATE        INDEX moz_places_originidindex      ON moz_places (origin_id)

CREATE TABLE moz_historyvisits (
   id                  INTEGER PRIMARY KEY,
   from_visit          INTEGER,
   place_id            INTEGER,
   visit_date          INTEGER,
   visit_type          INTEGER,
   session             INTEGER
)

CREATE INDEX moz_historyvisits_placedateindex ON moz_historyvisits (place_id, visit_date)
CREATE INDEX moz_historyvisits_fromindex      ON moz_historyvisits (from_visit)
CREATE INDEX moz_historyvisits_dateindex      ON moz_historyvisits (visit_date)

CREATE TABLE moz_inputhistory (
   place_id            INTEGER     NOT NULL,
   input               LONGVARCHAR NOT NULL,
   use_count           INTEGER,
   PRIMARY KEY (place_id, input)
)

CREATE TABLE moz_bookmarks (
   id                  INTEGER PRIMARY KEY,
   type                INTEGER,
   fk                  INTEGER DEFAULT NULL,
   parent              INTEGER,
   position            INTEGER,
   title               LONGVARCHAR,
   keyword_id          INTEGER,
   folder_type         TEXT,
   dateAdded           INTEGER,
   lastModified        INTEGER,
   guid                TEXT,
   syncStatus          INTEGER NOT NULL DEFAULT 0,
   syncChangeCounter   INTEGER NOT NULL DEFAULT 1
)

CREATE        INDEX moz_bookmarks_itemindex             ON moz_bookmarks (fk, type)
CREATE        INDEX moz_bookmarks_parentindex           ON moz_bookmarks (parent, position)
CREATE        INDEX moz_bookmarks_itemlastmodifiedindex ON moz_bookmarks (fk, lastModified)
CREATE        INDEX moz_bookmarks_dateaddedindex        ON moz_bookmarks (dateAdded)
CREATE UNIQUE INDEX moz_bookmarks_guid_uniqueindex      ON moz_bookmarks (guid)

CREATE TABLE moz_bookmarks_deleted (
   guid                TEXT PRIMARY KEY,
   dateRemoved         INTEGER NOT NULL DEFAULT 0
)

CREATE TABLE moz_keywords (
   id                  INTEGER PRIMARY KEY AUTOINCREMENT,
   keyword             TEXT UNIQUE,
   place_id            INTEGER,
   post_data           TEXT
)

CREATE UNIQUE INDEX moz_keywords_placepostdata_uniqueindex ON moz_keywords (place_id, post_data)

CREATE TABLE moz_anno_attributes (
   id                  INTEGER PRIMARY KEY,
   name                VARCHAR(32) UNIQUE NOT NULL
)


CREATE TABLE moz_annos (
   id                  INTEGER PRIMARY KEY,
   place_id            INTEGER NOT NULL,
   anno_attribute_id   INTEGER,
   content             LONGVARCHAR,
   flags               INTEGER DEFAULT 0,
   expiration          INTEGER DEFAULT 0,
   type                INTEGER DEFAULT 0,
   dateAdded           INTEGER DEFAULT 0,
   lastModified        INTEGER DEFAULT 0
)

CREATE UNIQUE INDEX moz_annos_placeattributeindex ON moz_annos (place_id, anno_attribute_id)

CREATE TABLE moz_items_annos (
   id                  INTEGER PRIMARY KEY,
   item_id             INTEGER NOT NULL,
   anno_attribute_id   INTEGER,
   content             LONGVARCHAR,
   flags               INTEGER DEFAULT 0,
   expiration          INTEGER DEFAULT 0,
   type                INTEGER DEFAULT 0,
   dateAdded           INTEGER DEFAULT 0,
   lastModified        INTEGER DEFAULT 0
)

CREATE UNIQUE INDEX moz_items_annos_itemattributeindex ON moz_items_annos (item_id, anno_attribute_id)

CREATE TABLE moz_meta (
   key                 TEXT PRIMARY KEY,
   value NOT NULL
) WITHOUT ROWID

protections.sqlite

CREATE TABLE events (
   id                  INTEGER PRIMARY KEY,
   type                INTEGER NOT NULL,
   count               INTEGER NOT NULL,
   timestamp           DATE
)

storage.sqlite

CREATE TABLE database (
   cache_version INTEGER NOT NULL DEFAULT 0
)

CREATE TABLE cache (
   valid               INTEGER NOT NULL DEFAULT 0,
   build_id            TEXT NOT NULL DEFAULT ''
)

CREATE TABLE repository (
   id                  INTEGER PRIMARY KEY,
   name                TEXT NOT NULL
)

CREATE TABLE origin (
   repository_id       INTEGER NOT NULL,
   origin              TEXT    NOT NULL,
   group_              TEXT    NOT NULL,
   client_usages       TEXT    NOT NULL,
   usage               INTEGER NOT NULL,
   last_access_time    INTEGER NOT NULL,
   accessed            INTEGER NOT NULL,
   persisted           INTEGER NOT NULL,
   PRIMARY KEY (repository_id, origin),
   FOREIGN KEY (repository_id) REFERENCES repository(id)
)

webappsstore.sqlite

CREATE TABLE webappsstore2 (
   originAttributes    TEXT,
   originKey           TEXT,
   scope               TEXT,
   key                 TEXT,
   value               TEXT
)

CREATE UNIQUE INDEX origin_key_index ON webappsstore2(originAttributes, originKey, key)

Index