Perl and J.R.R. Tolkien
If you want to make an significant contribution on Perl, you must read John Ronald Reuel Tolkien's Legendarium because most top-level .c files have a quotation from Tolkien's.
For example, sv.c has the below:
/* * 'I wonder what the Entish is for "yes" and "no",' he thought. * --Pippin * * [p.480 of _The Lord of the Rings_, III/iv: "Treebeard"] */
utf8.c has three!
/* * 'What a fix!' said Sam. 'That's the one place in all the lands we've ever * heard of that we don't want to see any closer; and that's the one place * we're trying to get to! And that's just where we can't get, nohow.' * * [p.603 of _The Lord of the Rings_, IV/I: "The Taming of Sméagol"] * * 'Well do I understand your speech,' he answered in the same language; * 'yet few strangers do so. Why then do you not speak in the Common Tongue, * as is the custom in the West, if you wish to be answered?' * --Gandalf, addressing Théoden's door wardens * * [p.508 of _The Lord of the Rings_, III/vi: "The King of the Golden Hall"] * * ...the travellers perceived that the floor was paved with stones of many * hues; branching runes and strange devices intertwined beneath their feet. * * [p.512 of _The Lord of the Rings_, III/vi: "The King of the Golden Hall"] */
If you recognized the quote about the Road above, you're in luck.
Most software projects begin each file with a literal description of each file's purpose. Perl instead begins each with a literary allusion to that file's purpose.
Like chapters in many books, all top-level Perl source files (along with a few others here and there) begin with an epigramic inscription that alludes, indirectly and metaphorically, to the material you're about to read.
Quotations are taken from writings of J.R.R. Tolkien pertaining to his Legendarium, almost always from The Lord of the Rings.