/usr/share/mana/data/help/index.txt is in mana-data 0.6.1-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | ##3 === INDEX ===
-> @@about|About Mana@@
-> @@changes|Recent Changes@@
-> @@commands|Commands@@
-> @@windows|Windows@@
-> @@support|Support@@
|