“…For example, SQuAD (Rajpurkar et al, 2016), a widely used question-answering dataset composed of Wikipedia articles from multiple domains, is often referred to as a single-domain dataset in domain adaptation works for simplicity (Hazen et al, 2019;Shakeri et al, 2020;Yue et al, 2021). This scenario is also common in text summarization, where many datasets consist of a bundle of domains for news articles (Grusky et al, 2018), academic papers (Cohan et al, 2018;Fonseca et al, 2022), and do-it-yourself (DIY) guides (Cohen et al, 2021). While models that learn from multiple domains are frequently used, their nature and behavior have hardly been explored.…”