After reading some meta posts, I've decided to post this question on MathOverflow since I didn't receive any comments or answers.

How to show that $$\int_0^1 \dfrac{\operatorname{Li}_2\left(\frac{x}{4}\right)}{4-x}\,\log\left(\dfrac{1+\sqrt{1-x}}{1-\sqrt{1-x}}\right)\,dx=\dfrac{\pi^4}{1944}.$$

I am going to have to look back through my papers to find how it was evaluated. It's been a while and I forget without doing it all over again.

Unless, someone wants to jump on it before I get back...please feel free.

I used a sub ($t=x/4$), parts, and the identity $\sum_{n=1}^{\infty}H_{n}^{(2)}x^{n}=\frac{Li_{2}(x)}{1-x}$

Maybe break it up using:

$$H_{n+1}^{(2)}-\frac{1}{(n+1)^{2}}=H_{n}^{(2)}$$

and/or

$$\sum_{n=1}^{\infty}\frac{x^{2n}}{(n+1)(2n+1)\binom{2n}{n}}=\frac{4(\sin^{-1}(\frac{x}{2}))^{2}}{x^{2}}$$

I get it now. This is related to the identity:

$$ \left( \sin^{-1}(z)\right)^4=\frac{3}{2}\sum_{k=1}^\infty\frac{H_{k-1}^{(2)}(2z)^{2k}}{k^2 \binom{2k}{k}} \quad |z|<1 $$