We've done these tests in the past and made fixes but @cscott felt that we could do one final round of testing after tweaking and dusting off all patches before merge and deploy.
- T266149#6752389: Dynamically adjust size from broken media - Filed as T273013
- T266149#6752491: Caption as link content for broken media - Filed as T273014
- T266149#6755826: Margin bottom only applies to thumbnails
- T266149#6759641: TimedMediaHandler sets width to 100%
- T266149#6781425: Rounding difference in galleries - Filed as T272186
- T266149#6788204: Various overflowing differences