I have accessed these files for both my grandfathers and their brothers and cousins. My grandfather's brother was killed in battle and so his mother (my great grandmother) later donated his letters to her. Anything in his military file (including enlistment documents, medical records, digitized copies of these letters, and newspaper articles about his death) were uploaded to his page on this site.
My grandfather was injured so seriously in WWI that he was eventually sent back to Canada. My brother and I were amazed to read his medical records and all other records about him all these years later. I am grateful to the Canadian government for digitizing and uploading all of these records for posterity.