manifesto

A  manifesto  is "a published verbal declaration of the intentions, motives, or views of the issuer, be it an individual, group, political party or government" according to Wikipedia - in summary there is no IndieWeb(Camp) manifesto.

No Manifesto
There is no "indieweb manifesto" nor "indiewebcamp manifesto".

IndieWebCamp does have but to call either of them a manifesto would be an exaggeration and inaccurate.
 * design principles
 * and a code-of-conduct

Other Manifestos
Separately from indieweb/indiewebcamp, there is:
 * 2014-11-04: User Data Manifesto 2.0 - Defining basic rights for people to control their own data in the internet age.
 * 2014-07-04: The ind.ie manifesto - a separate effort developed independently from the indiewebcamp community (i.e. no discussion of its creation on #indiewebcamp IRC, nor on this wiki).
 * 2001-05-17: The Independents Day Manifesto - some original inspiration that planted some of the seeds of the IndieWeb movement.