Martin, this reminds me very much of H&W Control film of the '70s.(posted 8760 days ago)There were two H&W films; one was an Agfa microfilm of EI 16 and the other was an Agfa copy film of EI 80. Both were developed in H&W's proprietary developers, which I suspect was a POTA concentrate; it was sold in small air-excluding ampoules to be mixed immediately before use.
The EI 80 film, H&W VTE, for which Kodak High Contrast Copy Film could be substituted, was very much like today's Tech Pan except that it had rather reduced red sensitivity.
The slow film, VTE Ultra, was another matter. With careful work I could get prints that showed much higher sharpness, an overall combination of resolution and local contrast, than I can get with Tech Pan developed in anything. VTE Ultra was also panchromatic.
Now...I can get EI 50 with TP with reasonable contrast (Ethol TEC 1:15)...so the speed claimed for Gigabitfilm, assuming it's some sort of microfilm, to achieve a higher speed for the same quality 25 years later isn't unreasonable.
H&W vanished due to lack of demand. That Kodak has essentially shut down R&D in b&w materials and Agfa has dropped APX 25 reflects a market that doesn't bode well for Gigabitfilm.
It'd be interesting to learn what Gigabit's developer is.