Optimized refers to replacing legacy scripts with witness programs. P2PKH and P2SH outputs are replaced with 20 and 32 byte hashes respectively. Other output types are unaffected. Each input script is moved to the witness part if the corresponding witness is empty, otherwise the witness is kept and the script is removed.
On average, block weight would be reduced by …% and blocks would use …% of the weight limit (4M).
Copyright 2018 Paul Georgiou. This work is licensed under a Creative Commons Attribution 4.0 International License.