Xapian is an Open Source Search Engine Library, released under the GPL v2+. It's written in C++, with bindings to allow use from Perl, Python 2, Python 3, PHP 5, PHP 7, Java, Tcl, C#, Ruby, Lua, Erlang, Node.js and R (so far!)
v1.4.22#2
(!arm | arm64) & !uwp & !xbox
GPL-2.0-or-later
Manifest