The ma and ac tags indicate whether the molecule that produces a CCS read is missing a SMRTbell adapter on its left/start or right/end. The tags produced by ccs v6.3.0 and newer are based on the ADAPTER_BEFORE_BAD and ADAPTER_AFTER_BAD information in the subread cx tag.
Array containing four counts, in order:
detected adapters on left/start
missing adapters on left/start
detected adapters on right/end
missing adapter on right/end
Bitmask storing if an adapter is missing on either side of the molecule. A value of 0 indicates neither end has a confirmed missing adapter.