There are no standards for what constitutes an "E-bike" specific component, so differences compared to "standard" chains are really up to what the manufacturer sees as being e-bike requirements (i.e., manufacturer specific).
To better understand some of the general changes manufacturers might make, we could look to e-bike specific tires as he tire physical specifications are well documented on the web (e.g., tread and sidewall thickness). Most "e-bike" marketed tires are heavier, thicker and likely a little bit more robust than "regular" tires, but generally very similar to "regular" tires. That said, if you know the market you can typically find "regular" tires with these features as well, but these will be marketed for different purposes (e.g., touring).
The internal specification of chains are less well documented, so we have to do some educated guess work. Currently, the e-bike market is viewed as being more casual cyclists (e.g., many "dedicated" cyclists will still break into conniptions when the mere word is mentioned). This market segment is less concerned with weight and "performance" as getting something that is strong and reliable that they can neglect. As such, I suspect (i.e., speculation) the chains will have some sort of nickel plating or extra nickel plating to reduce corrosion, but will avoid any weight saving features (e.g., "performance" features such as hollow rivets and/or hollow plates). This might make it a little more "robust" compared to most high-end chains for shifting under load which, when considering the segment, will be a desirable feature. That said, nickel plating can also be found on "regular" chains, but these chains will also feature weight saving features such as hollow rivets and/or hollow plates (or some combination therein). Because there are tight tolerances on 11 speed chain dimensions, any differences will be largely one of material selections.
In terms of chain longevity the nickel plating will have the biggest effect, but as mentioned this feature can already be found on other high-end "regular" chains which typically cost the same or slightly less than e-bike specific chains. So I am not clear whether you will find any tangible gains in longevity by using an e-bike chain, unless you are consistently breaking chains by shifting under loads or running poor chain lines.
As an aside, if maximizing longevity is your key concern, you should consider hot waxing a chain. Typically, I get roughly twice the longevity on an 11 speed chain (scroll to the bottom figure and compare the wear rates, i.e., line slopes).
