/usr/include/Swiften/TLS/ is in libswiften-dev 2.0+dev6-1+b1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/Swiften/TLS/BlindCertificateTrustChecker.h
/usr/include/Swiften/TLS/CAPICertificate.h
/usr/include/Swiften/TLS/Certificate.h
/usr/include/Swiften/TLS/CertificateFactory.h
/usr/include/Swiften/TLS/CertificateTrustChecker.h
/usr/include/Swiften/TLS/CertificateVerificationError.h
/usr/include/Swiften/TLS/CertificateWithKey.h
/usr/include/Swiften/TLS/OpenSSL/
/usr/include/Swiften/TLS/OpenSSL/OpenSSLCertificate.h
/usr/include/Swiften/TLS/OpenSSL/OpenSSLCertificateFactory.h
/usr/include/Swiften/TLS/OpenSSL/OpenSSLContext.h
/usr/include/Swiften/TLS/OpenSSL/OpenSSLContextFactory.h
/usr/include/Swiften/TLS/PKCS12Certificate.h
/usr/include/Swiften/TLS/PlatformTLSFactories.h
/usr/include/Swiften/TLS/Schannel/
/usr/include/Swiften/TLS/Schannel/SchannelCertificate.h
/usr/include/Swiften/TLS/Schannel/SchannelCertificateFactory.h
/usr/include/Swiften/TLS/Schannel/SchannelContext.h
/usr/include/Swiften/TLS/Schannel/SchannelContextFactory.h
/usr/include/Swiften/TLS/Schannel/SchannelUtil.h
/usr/include/Swiften/TLS/ServerIdentityVerifier.h
/usr/include/Swiften/TLS/SimpleCertificate.h
/usr/include/Swiften/TLS/TLSContext.h
/usr/include/Swiften/TLS/TLSContextFactory.h
/usr/include/Swiften/TLS/TLSError.h