This used to be a really easy question to answer – Adobe. The PDF file format was invented by the co-founder of Adobe (John Warnock) 20 years ago and Adobe would usually release new versions every couple of years. The first version was 1.0 and they then increased by a point (1.1, 1.2, etc). Looking through the releases is a fascinating look at how technology and business has evolved over the last 20 years – you can see not only the new technologies and trends but also the shifting alliances between companies.
Adobe also made the details publically available and you could download the file in electronic file format (PDF naturally). Some versions were also released as printed books – I still have a well-thumbed copy of the 1.6 release. Adobe was a good custodian of the PDF file format and regularly released new versions accompanied by new versions of Acrobat and Reader.
But 1993 was a very different world and there was far less emphasis on open standards. In today’s world, proprietary standards struggle. Adobe realised that to continue to thrive, the PDF file format needed to become an Open Standard.
So in 2008, Adobe set it free and handed the specification over to the International Organization for Standardization. This is an Open Body setup so maintain and develop many standards including the PDF file format (which is now known as ISO 32000). You may feel that there is a slight irony in that now the file format is ‘free’ you will have to pay for a copy from ISO because it is no longer effectively subsidised by Adobe (and ISO needs revenue to maintain the development).
Because the PDF file format is now developed by a committee development tends be be slower, but anyone can now be involved. Adobe continues to be an important and influential part of this development but anyone can get involved and influence the discussion.
So the answer the question could well be you! Are you interested?