These binaries were all built from SeaMonkey's 2.53 GitLab repositories, off the 2_53_15_beta_01 branch, and Mozilla's repositories for the extensions, off the default branch, with the following commands used to obtain the sources: git clone -b 2_53_15_beta_01 https://gitlab.com/seamonkey-project/seamonkey-2.53-mozilla.git comm-253 cd comm-253 git clone -b 2_53_15_beta_01 https://gitlab.com/seamonkey-project/seamonkey-2.53-comm.git comm A source code tarball with the contents of all the repositories, ready to build, is available for download from the source/ subdirectory here on FTP. For the l10n source, these are from SeaMonkey's 2.53 GitLab repositories, off the 2_53_15_beta_01 branch, with the following commands used to obtain the source: git clone -b 2_53_15_beta_01 https://gitlab.com/seamonkey-project/seamonkey-2.53-l10n.git l10n-253 A source l10n tarball with the contents of l10n-253 in such a checkout is available for download from the source/ subdirectory here on FTP. This directory contains precompiled binaries of SeaMonkey 2.53.15b1 Read https://www.seamonkey-project.org/dev/ for instructions on how to build your own copy of SeaMonkey. Language packs are available from the langpacks/ subdirectory and can be installed as add-ons and switched to using the Appearance preferences. linux-i686 and linux-x86_64 .tar.bz2 files are tarball builds for Linux on the x86 and x86_64 platforms. mac/ .dmg files are self-mounting disk images for macOS. The .exe files in win32/ and win64/ are the main win32/win64 release installers respectively, letting you chose which extensions to install. The .zip files in win32/ and win64/ contain a full optimized build without an installer. Accessibility and MAPI OS integration are not available if you use a zipped Windows build. If you do not understand how to get this to run, you should use installer.exe instead. Please read the release notes at https://www.seamonkey-project.org/releases/seamonkey2.53.15/