I would note that what you get in an internet forum is not -really- "information" as much as "opinions",
and
I am pretty sure that you will not see an "autodata" sort of information source any time soon, I am pretty sure all the US based forklift manufacturers and their dealers would not agree to supply this information, and will have their legal department send a "cease and desist" order to anyone that tries to become an 'autodata' sort of information source. the information is considered 'proprietary intellectual property' and they have a contractual and legal need to pursue anyone who violates their rights to keep the information proprietary/secret.

I'm not sure how the laws are on your side of the pond, but over here end consumers are protected by "Consumer Protection Laws" which require auto manufacturers to make the info on their products public. There is no such law for any type of industrial equipment. The large truck manufacturers make some of their info available to be more competitive but none of the forklift manufacturers have followed suit.

This forum on Forkliftaction is your best bet to get any information on brands you're not a dealer on. I think the word is "Priceless"

I don't think there will be one in the near future. In the automotive industry they have a common interface connector OBDII (i think). With forklifts. One manufacture could have more than 1 lead with more than one connector. Some have different software for the truck and different for the engine. I agree in an ideal world it would be great. But the OEMS don't want you working on there equipment, especially without any training. Some forklifts for example VNA man up trucks are very complex and vary massively from one manufature to another. You could know how to fix a linde VNA then see a BT VNA and have no clue at all. With cars most manufactures use similar ideas and designs.

Just what I know, There is not any truck software including full info about differents brands.

Regards