Errors

ERROR CODES
  E_VERSION E_BAD_KEY E_DOT_RESERVED E_BAD_COLOR E_DUP_KEY E_PALETTE_AFTER_GRID
  E_PALETTE_FILE E_BAD_ROW E_ROW_WIDTH E_UNKNOWN_KEY E_EMPTY_FRAME E_NO_FRAMES
  E_BAD_ID E_DUP_FRAME E_MIXED_FRAMES E_BAD_ARG E_VARIANT_KEY E_UNKNOWN_SECTION
  E_SELECT E_KEY_CONFLICT E_TILE_SIZE E_FILE
  Every error line starts with the command ('ellipse: E_BAD_ARG: cy=1.5 and ry=1 ...'). An
  error in an input file also says which input it came from, then where in the file:
  'compose: layer 2 (parts.px:hat): parts.px:4: E_ROW_WIDTH (frame hat, ...'.
  A file that can't be read is one E_FILE line too (see FORMAT: paths).
  Inputs are named like -h names them: FILE, SRC, --into, -o, OUT, A/B, layer N, item N,
  file N (the Nth of several), --map, --palette, stdin. check reports per file instead.
  A command that fails prints none of its notes or WARNINGs: they describe the write it was
  about to make (a grid renamed, keys rekeyed), and nothing was written.