  In quantum field theories defined on a spacetime with boundaries, the
entanglement entropy exhibits subleading, boundary-induced corrections to the
ubiquitous area law. At critical points described by conformal field theories
(CFTs), and when the entangling surface intersects the physical boundary of the
space, new universal terms appear in the entropy and encode valuable
information about the boundary CFT. In $2+1$ dimensions, the universal
subleading boundary term is logarithmic with coefficient $b(\theta)$ depending
on the angle $\theta$ at which the entangling surface intersects the boundary,
as well as on the boundary conditions (BCs). In this paper, we conduct a
numerical study of $b(\theta)$ for free bosons on finite-size square lattices.
We find a surprisingly accurate fit between our lattice results and the
corresponding holographic function available in the literature. We also comment
on the ratio $b''(\pi/2)/A_T$, where $A_T$ is the central charge in the near
boundary expansion of the stress tensor, for which a holographic analysis
suggests that it may be a universal quantity. Though we show evidence that this
ratio is violated for the free boson with Dirichlet BCs, we conjecture its
validity for free bosons evenly split between Dirichlet and Neumann BCs.
