Intermediate release before some big and scary changes that require more testing.

Changelog for both GUI and CLI:

• Fix SAN disambiguation for kings in variants with multiple kings
• Fix bug that interpreted some very high scores as mate scores
• Option to play each opening n times
• Option to NOT swap sides between paired engines
• Play repetitions properly when using a Polyglot book
• Fix bug in Janus Chess SAN move parsing
• Add the "Variant" tag to the minimal PGN tag roster for non-standard chess
• Fix "whitepov" mate scores for UCI engines
• GameDuration, GameStartTime and GameEndTime PGN output tags
• Fix automatic creation of ECO tags when the opening file already contains those tags
• Don't reset fifty-moves counting when castling (obey FIDE rules)
• Option for game length-based draw adjudication
• Allow longer initialization period for engines (Leela Chess Zero needed this)
• Pyramid tournament type
• Option to discard unfinished games from PGN output
• An illegal move claim by an Xboard engine is considered a forfeit (Cute Chess doesn't forward illegal moves to engines)
• Set PGN tags for White and Black when starting a game
• Game adjudication via "trusted" mate scores
• 64-bit node limits
• Option to use two-sided scores for resign adjudication
• Fine-grained control over when to pick new openings in different tournament modes
• Gauntlet tournaments can have multiple seeded players
• Fix issue where UCI_Variant is sent without a value
• Do not incorrectly send UCI_Standard to engines without that option
• Parse halfmove clock and fullmove number from epd opening files
• Fix and generalize the book start option
• Support hourglass time control
• Extended output of tournament results
• Add time increment also before the first move

GUI-only changes:

• Option to close the default game tab if it's unused when a game/tournament is started
• Configurable default PGN output file for games and tournaments
• User can adjudicate ongoing games manually
• Tournament cannot be started with duplicate engine display names
• Fix crash when trying to set path options (eg. INI file path) for an engine
• Show search speed in NPS for values below 10000, else in KNPS
• Show pondermove and ponderhit for UCI engines even with pondering disabled
• The user (human player) can resign their game via a menu item
• Option to display sides of players on chess clock
• Option to use full user name instead of login name as the human player's display name
• Option to choose whether a human player can play after timeout
• Option to copy PGN of current game (in main window) to clipboard
• Move list can be scrolled with the keyboard
• Proper animations for reversed moves
• Show NPS reported by engines instead of trying to calculate it
• The user cannot save invalid engine settings
• Fix bug where gui would hang if an engine failed to start
• Chess board coordinates (rows and columns)
• Open game tab even if an engine is still loading
• "Paste FEN" menu item
• Game and position export to clipboard from game database
• If a Variant tag is present, display variant as label in GameDatabaseDialog
• Add engines to tournament by double-clicking
• Bugfix: Update displayed tags for finished tournament games
• Show evaluation history for finished tournament games
• Remove status bar
• Don't wrap long lines in evaluation table
• New shortcut for board flipping
• Option to enable automatic flipping of board for human vs human games
• Fix display of evaluation history for games with Black starting positions
• Engine configurations can be cloned
• Use file selector for options with name ending in "Path" or "File"

CLI-only changes:

• Option to save the end position of games to a FEN file
• Add LOS, DrawRatio and percentage of SPRT match status to output

New chess variants:

• Andernach, Anti-Andernach, Super-Andernach
• Knightmate
• Grid Chess, Displaced Grid Chess, Berolina Grid Chess, Slipped Grid Chess
• Antichess / Losing Chess, Giveaway Chess, Suicide Chess
• Two Kings Each Chess (Wild 9), Symmetrized Wild 9
• Three Kings Chess
• Pocket Knight Chess
• Co-regal Chess
• Embassy Chess
• Chancellor Chess (9x9), Modern Chess (9x9)
• Gryphon Chess, Change-Over Chess, Circular Gryphon Chess, Simplified Gryphon Chess
• Shatranj, Courier Chess (Medieval)
• S-Chess (Seirawan Chess)
• ASEAN-Chess, Ouk Chatrang (Cambodian Chess), Kar Ouk (One-check Ouk), Makruk (Thai Chess)
• Grand Chess
• Sittuyin (Myanmar Chess)
• Ai-Wok (Makruk variant)
• Los Alamos Chess
• Almost Chess
• Amazon Chess
• Chigorin Chess
• Rifle Chess, Shoot Chess
• Game of Codrus (Losing Chess Variant)
• Placement Chess
• Hoppel-Poppel (has N/B hybrids), New Zealand Chess (has N/R hybrids)
• Jeson Mör
• Gustav III's Chess
• Shogi (Japanese Chess), Minishogi, Dobutsu Shogi, EuroShogi, Judkins Shogi