Rebase our Thunderbird custom package on top of 52.5.2
Originally created by @intrigeri on #15033 (Redmine)
Feature Branch: feature/15033-thunderbird-52.5.2-2
Related issues
- Blocks #13245 (closed)
Originally created by @intrigeri on #15033 (Redmine)
Feature Branch: feature/15033-thunderbird-52.5.2-2