A good user was affected by a global IP range block and the block message referred this to 89.144.221.0/24. He went to https://meta.wikimedia.org/wiki/Special:Contributions/89.144.221.0/24 where you can find the following block messages:

This IP address is currently blocked. The latest block log entry is provided below for reference:

• 14:09, 21 May 2018 Green Giant (talk | contribs | block) blocked 89.144.220.0/22 (talk) with an expiration time of 1 year (anonymous users only, account creation disabled, cannot edit own talk page) (Long-term abuse: per request (if you are affected by this block, please [stewards@wikimedia.org contact us]) (unblock | change block)

This IP address is currently globally blocked. The global block log entry is provided below for reference:

• 14:09, 21 May 2018: Green Giant (meta.wikimedia.org) globally blocked 89.144.220.0/22 (expires on 21 May 2019 at 14:09, anonymous only) (edits · IP check · whois) (Long-term abuse: per request (if you are affected by this block, please [stewards@wikimedia.org contact us]) (remove | modify)

However, both these blocks are anonymous only. The global block without anon-only that really affected him was https://meta.wikimedia.org/wiki/Special:Log?type=gblblock&page=User:89.144.221.0/24

18:41, 7 May 2018 Ruslik0 (talk | contribs | block) globally blocked User:89.144.221.0/24 (expiration 18:41, 7 May 2019) (Long-term abuse)

For stewards who want to set a new range block, there is no way to identify whether a smaller or bigger range is already blocked and what settings it has, or not.

Two things could be improved (if useful, split this into two bug reports):

• (short term) show all log entries that affect a range on Special:Contributions
• (long term) let the global blocking system check if there is already a smaller or bigger range blocked