Are you a Linux user who wants to build Thunderbird? Here's a tutorial on how to setup a development environment in Ubuntu, in just a few commands! This is helpful if you're interested in fixing bugs, trying out patches, or making any local changes to Thunderbird.
Tutorial Commands:
Setup tools needed to build Thunderbird
$ sudo apt install python3-pip mercurial
Checkout the source code
$ mkdir tb-build && cd tb-build
$ hg clone https://hg.mozilla.org/mozilla-central source
$ cd source/
$ hg clone https://hg.mozilla.org/comm-central comm
Run the bootstrap command from the source directory. Choose 2 (to build Firefox for Desktop). Choose all of the default options.
$ ./mach bootstrap
Create your mozconfig file in the source directory with the following info
$ vim mozconfig
ac_add_options --enable-project=comm/mail
Build Thunderbird!
$ ./mach build
Run what you just built!
$ ./mach run