"open source, software development platform"
A list of questions/documentation/reports that any good service provider should have readily available!
Taskwarrior is a command-line todo list manager.
"It maintains a list of tasks that you want to do, allowing you to add/remove, and otherwise manipulate them. Task has a rich list of subcommands that allow you to do sophisticated things with it. You'll find it has customizable reports, charts, GTD features, Lua extensions, device synching and more."
"w2do is a simple to use, yet efficient cross-platform command-line todo manager written in Perl, and capable of export to HTML 4.01 Strict as well as to plain text."
If you don't like OTRS and you look for an alternative to RT check out Roundup!