Many historical documents that have been digitized have undergone OCR, or optical character recognition, a process where the images of the text have been transcribed to make them keyword searchable. This process captures the words as they appeared, including outdated anglicisations or racist terms that we would no longer use today.
Including such terms when conducting keyword searches of newspaper or other primary source databases can expand the number of results for your search. For instance, if you are searching for references to Beijing, you may want to also search for Peking.