截至2019.8.6日，webrtc官網release了M76，具體可參考：release notes
WebRTC分支提交記錄可以查看git commit記錄。
方法：git checkout 到特定分支，使用git log命令查看最上面的提交記錄即為該分支最后的提交記錄。
| remotes/branch-heads/70 |
4ab51cb6d7d4530b344e63ed8274d1454b7a5f39 |
| remotes/branch-heads/71 |
0ba24191ee90c70679d2452363676c2d65b6b751 |
| remotes/branch-heads/72 |
80865776cf8a1a811166ee005951b7f5b01deacd |
| remotes/branch-heads/m73 |
8bb9968c6c8643b108e1e972bf77256a97588890 |
| remotes/branch-heads/m74 |
cc1b32545db7823b85f5a83a92ed5f85970492c9 |
| remotes/branch-heads/M75 |
159c16f3ceea1d02d08d51fc83d843019d773ec6 |
| remotes/branch-heads/m76 |
9863f3d246e2da7a2e1f42bbc5757f6af5ec5682 |
| remotes/branch-heads/m77 |
ad73985e75684cb4ac4dadb9d3d86ad0d66612a0 |
| remotes/branch-heads/m78 |
... |
進行同步時，可以指定特定分支。如需同步M74分支：
# gclient sync -r cc1b32545db7823b85f5a83a92ed5f85970492c9