Is there a joint test of model coefficients, effectively testing for main and interaction effects in quantile linear mixed model?

I am just reading this paper: Linear Quantile Mixed Models: The lqmm Packagefor Laplace Quantile Regression. Let us assume I have a repeated observation experiment, where I want to assess the effect of time, some "factor" (say A and B) and interaction between them. The model reports coefficients, but how to test them jointly, in the spirit of the ANOVA deviance table for the GLM? Or how to test the differences between, each time point and the initial time point and report confidence intervals for it? I guess it can be done via bootstrap, but how about the p-values for the main effects?