The VRT has been spending a lot of time on the PDF format lately. Most everything you really are going to worry about occurs in association with either the obj tags or Javascript tags. Adobe has to support extended characters for the various languages around the world. This is done by placing the ASCII hexadecimal value for the character you are representing immediately after a # character. So the following object string could be represented as:/Typ#65/#41#63t#69#6fn/S/#4a#61#76a#53cript/J#53″]
Source: https://blog.talosintelligence.com/2010/04/matts-primer-for-pdf-analysis.html