I believe Fennel was originated by Phil Hagelberg (technomancy)

https://git.sr.ht/~technomancy/fennel-lang.org

Janet looks like is by Calvin Rose (bakpakin) https://github.com/janet-lang/janet/graphs/contributors

I’m pretty sure Calvin created Fennel and Phil took up the reins when Calvin moved on from the project.

I stand corrected:

    % git remote -v
    origin https://git.sr.ht/~technomancy/fennel (fetch)
    origin https://git.sr.ht/~technomancy/fennel (push)

    % git log --reverse
    commit 9afe4338ed1816a759cb4b120f89e8f67159ce16
    Author: Calvin Rose <calsrose@gmail.com>
    Date:   Sun Aug 7 18:50:34 2016

        First commit.

    commit b62a24853e24662f76932a2a81bb77cc25704491
    Author: Calvin Rose <calsrose@gmail.com>
    Date:   Sun Aug 7 19:05:40 2016

        Add some examples.

    commit 5e3e0fe11e4f56007b3523e54d81d55280ef2204
    Author: Calvin Rose <calsrose@gmail.com>
    Date:   Tue Aug 9 08:27:43 2016

        Update README.md