$ git grep -iE '[^0-9a-z]520[^0-9a-z]' -- "*.cpp" "*.h"
src/net_processing.cpp:        // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object,
src/outputtype.cpp:    // Note that scripts over 520 bytes are not yet supported.
src/policy/policy.cpp:        // keys (remember the 520 byte limit on redeemScript size). That works
src/script/descriptor.cpp:            if (script_size + 3 > 520) {
src/script/descriptor.cpp:                error = strprintf("P2SH script is too large, %d bytes is larger than 520 bytes", script_size + 3);
src/script/script.h:static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520;
src/test/descriptor_tests.cpp:    CheckUnparsable("sh(multi(16,KzoAz5CanayRKex3fSLQ2BwJpN7U52gZvxMyk78nDMHuqrUxuSJy,KwGNz6YCCQtYvFzMtrC6D3tKTKdBBboMrLTsjr2NYVBwapCkn7Mr,KxogYhiNfwxuswvXV66eFyKcCpm7dZ7TqHVqujHAVUjJxyivxQ9X,L2BUNduTSyZwZjwNHynQTF14mv2uz2NRq5n5sYWTb4FkkmqgEE9f,L1okJGHGn1kFjdXHKxXjwVVtmCMR2JA5QsbKCSpSb7ReQjezKeoD,KxDCNSST75HFPaW5QKpzHtAyaCQC7p9Vo3FYfi2u4dXD1vgMiboK,L5edQjFtnkcf5UWURn6UuuoFrabgDQUHdheKCziwN42aLwS3KizU,KzF8UWFcEC7BYTq8Go1xVimMkDmyNYVmXV5PV7RuDicvAocoPB8i,L3nHUboKG2w4VSJ5jYZ5CBM97oeK6YuKvfZxrefdShECcjEYKMWZ,KyjHo36dWkYhimKmVVmQTq3gERv3pnqA4xFCpvUgbGDJad7eS8WE,KwsfyHKRUTZPQtysN7M3tZ4GXTnuov5XRgjdF2XCG8faAPmFruRF,KzCUbGhN9LJhdeFfL9zQgTJMjqxdBKEekRGZX24hXdgCNCijkkap,KzgpMBwwsDLwkaC5UrmBgCYaBD2WgZ7PBoGYXR8KT7gCA9UTN5a3,KyBXTPy4T7YG4q9tcAM3LkvfRpD1ybHMvcJ2ehaWXaSqeGUxEdkP,KzJDe9iwJRPtKP2F2AoN6zBgzS7uiuAwhWCfGdNeYJ3PC1HNJ8M8,L1xbHrxynrqLKkoYc4qtoQPx6uy5qYXR5ZDYVYBSRmCV5piU3JG9))","sh(multi(16,03669b8afcec803a0d323e9a17f3ea8e68e8abe5a278020a929adbec52421adbd0,0260b2003c386519fc9eadf2b5cf124dd8eea4c4e68d5e154050a9346ea98ce600,0362a74e399c39ed5593852a30147f2959b56bb827dfa3e60e464b02ccf87dc5e8,0261345b53de74a4d721ef877c255429961b7e43714171ac06168d7e08c542a8b8,02da72e8b46901a65d4374fe6315538d8f368557dda3a1dcf9ea903f3afe7314c8,0318c82dd0b53fd3a932d16e0ba9e278fcc937c582d5781be626ff16e201f72286,0297ccef1ef99f9d73dec9ad37476ddb232f1238aff877af19e72ba04493361009,02e502cfd5c3f972fe9a3e2a18827820638f96b6f347e54d63deb839011fd5765d,03e687710f0e3ebe81c1037074da939d409c0025f17eb86adb9427d28f0f7ae0e9,02c04d3a5274952acdbc76987f3184b346a483d43be40874624b29e3692c1df5af,02ed06e0f418b5b43a7ec01d1d7d27290fa15f75771cb69b642a51471c29c84acd,036d46073cbb9ffee90473f3da429abc8de7f8751199da44485682a989a4bebb24,02f5d1ff7c9029a80a4e36b9a5497027ef7f3e73384a4a94fbfe7c4e9164eec8bc,02e41deffd1b7cce11cde209a781adcffdabd1b91c0ba0375857a2bfd9302419f3,02d76625f7956a7fc505ab02556c23ee72d832f1bac391bcd2d3abce5710a13d06,0399eb0a5487515802dc14544cf10b3666623762fbed2ec38a3975716e2c29c232))", "P2SH script is too large, 547 bytes is larger than 520 bytes"); // P2SH does not fit 16 compressed pubkeys in a redeemscript
src/test/miner_tests.cpp:    std::vector<unsigned char> vchData(520);