For those who are interested in more information about specific phenomena discussed in some topics and especially occurring in unformal register texts, the following reading can be a good starting point: Sanguinetti, Bosco, Cassidy et al - (2023) "Treebanking user-generated content: a UD based overview of guidelines, corpora and unified recommendations". Language Resources & Evaluation (2023) 57:493–544 (https://link.springer.com/content/pdf/10.1007/s10579-022-09581-9.pdf)