It lets you cross reference and document any language with gigabytes of code, e.g. Android platform code. Jelly bean ~9 gb of code.
Try it out: http://www.srcmap.org/s/sl.htm/p=android-4.2.2_r1
Sample Documents created from that app are here:
http://www.srcmap.org/p/1/4af293f91271/Android_Init_startup_...
http://www.srcmap.org/p/1/80c16319d25e/Docker.html
http://www.srcmap.org/p/6/4a88339ceef3/mtpd_source_code_stud...
http://www.srcmap.org/p/1/212c9a285186/Google_IO_2014____sch...
The ux is ok. A few gigabytes of code db running in a cheapest $5 instance of Digital Ocean.
The app is very simple ~8 mb of standalone binary, no external dependency do any other app/db.