HTC has pushed out the kernel source code for its U11+ phone which means that anyone who is a developer for apps or other types of content, will have what they need to get started on working with the specifics in regards to the software and compatibility of the device with their creations. Kernel source code can be used for quite a few different things but an always-easy example to point out is the ability for third-party developers and just generally anyone who likes to tinker with devices and software to develop or hack together custom firmware for the phone. In this case, the HTC U11+.
With the kernel source code out there now, anyone who creates custom firmware (ROMs) for other devices can do so for the HTC U11+ if they so choose, and while the kernel source code for this device doesn't really do much for the users of the phone, at least not in a direct way, it eventually has the potential to lead to other things that will be user-facing, such as improvements to applications, the custom firmware as mentioned above, or other types of content like games or even custom recoveries.
For those that are wanting to download and make use of the kernel source code for this device from HTC, there are four different downloadable files to pick up, three of them being listed under the carrier tag of HTC Asia, and the final being listed under the carrier tag of HTC. What this is referring to is the model of the device based on region. In fact the region is listed in the column just to the right of the carrier column, so it's important to make sure to pay attention to these so you grab the right files. Each file is 417MB in size so the download is a decent size but it's not too hefty that it should cause anyone any problems, unless you're literally running low on space and have none to spare or, happen to be connected to the internet on a very slow connection which would result in a much longer download time.