private void loadEntry(String entry) {
        if (entry.contains(":")) {
            // new format
            Iterator<String> parts = KV_SPLIT.split(entry).iterator();

            if (!parts.hasNext()) return;
            String uuidPart = parts.next();

            if (!parts.hasNext()) return;
            String usernamePart = parts.next();

            UUID uuid = Uuids.fromString(uuidPart);
            if (uuid == null) return;

            this.lookupMap.put(uuid, usernamePart);
        } else if (entry.contains("=")) {
            // old format
            Iterator<String> parts = LEGACY_KV_SPLIT.split(entry).iterator();

            if (!parts.hasNext()) return;
            String usernamePart = parts.next();

            if (!parts.hasNext()) return;
            String uuidPart = parts.next();

            // contains a time
            if (uuidPart.contains("|")) {
                Iterator<String> valueParts = LEGACY_TIME_SPLIT.split(uuidPart).iterator();
                if (!valueParts.hasNext()) return;
                uuidPart = valueParts.next();
            }

            UUID uuid = Uuids.fromString(uuidPart);
            if (uuid == null) return;

            this.lookupMap.put(uuid, usernamePart);
        }
    }
Gets the most recent username used by a given uuid

@param uuid the uuid to lookup with
@return a username, or null
common/src/main/java/me/lucko/luckperms/common/storage/implementation/file/FileUuidCache.java