PlatformIO gives you the library version that the LVGL upload in the registry.
As one can see in here
they uploaded the 8.0.0 version to PlatformIO 3 months ago (16th March 2021). Yet the file you’ve shown was changed 14 days ago and is also tagged as 8.0.0.
I have no idea what the LVGL people are doing there, releasing the library to PlatformIO and then keep on developing it, under the same version tag, on their github, changing it significantly. As said, PlatformIO gives you the library version uploaded by them, which is e.g. this file as of 16th March 2021.
There is also an issue with library’s default version recommendation making PlatformIO crash, as I’ve reported here, but that’s a separate issue.
There is also a related topic at Problem with pio lib install "lvgl/lvgl".
Really, if you want the LVGL version that matches the one at the github, you should be referring to their gitrepo and a specific branch or commit, say e.g. with
lib_deps =
https://github.com/lvgl/lvgl.git#v8.0.0
(this repo#branch syntax is allowed per docs)
Then you will be getting what is in the repo for that tag. (which still seems to be changing a lot for a fixed version…)
Edit: In issue has been opened in https://github.com/lvgl/lvgl/issues/2315