Within RSA Archer, the History Log shows the message: History Log entry truncated and not compared due to excessive length. The functionality to compare values stored in History Log was crippled for strings longer than 2000 characters. This was because large strings (>100,000 characters) would run very slowly and often cause the user to click repeatedly. This action would queue up enough requests to run the string comparisons that environments were rendered unresponsive.
Click the Export button and export to a file to view the values.
There is an Enhancement Request in place, ARCHER-5333, for this to allow the full entry. Until this feature is brought into the product you can use the API tool from the community https://community.rsa.com/docs/DOC-32414 to view the full field value. The screenshot below shows how this can be done.
Other than using API, the whole history is also stored within the Archer Instance Database and can be obtained via SQL. In addition, please refer to this link for other workarounds - https://community.rsa.com/message/879317.