Language Learning with Netflix is an AMAZING extension. It’s actually the best extension I’ve ever used. I used to have to take really long methods of doing this kind of thing myself (finding the show in Japanese, finding Japanese subtitle files, making sure they were in sync, exporting them to a new file, all so the subtitle text in the video is selectable for easier lookup and flash card making).
LLN makes this process so painless that my other methods feel archaic by comparison! I cannot stress how much I love this extension. Thank you SOOOOOO much for making it! I am more than happy to pay to support its development.
Also, I am a programmer of some capability. I work for Handelabra Games making digital versions of tabletop games, such as Sentinels of the Multiverse. I say this not to advertise but as credentials. If you are looking for help in developing LLN I would be more than happy to offer myself to the cause. I don’t have a ton of free time right now, but if there’s some smaller feature that I could help with I’d love to do so. Please let me know. 
If not programming, then at least it would be nice to have a way to help correct some machine misinterpretations in the subtitles. For example, in an episode of Doraemon I was watching, the kanji was 他, which should have furigana correctly written as ほか (hoka) by itself, and this is indeed what Nobita says, but in LLN it shows it as た (ta). Other times, it automatically separates two words that actually belong together to form a different word. For example, I saw the word 幻想的, but it identified it as two separate words: 幻想 and 的. Although these words do exist on their own, they also can be combined together to make a word. If there were a way the viewer could manually correct these inaccuracies for others, I’d put in the effort to do as I come across things that need adjustments.
Either way, thank you very much for making such a fantastic extension; it has allowed me to spend much less time preparing learning material and more time actually learning.